How to express something given to a customer for "free in a non-immoral, non-sexual, non-promoting context"?

Some various translations shown at linguee suggest that terms like bonus, discount, discount in kind, in-kind rebate, rebate in kind, or redeemable in kind would be neutral terms (not suggestive of graft or kickbacks occurring) for translation of Naturalrabatt. (Note, in this context, "in kind" is a more-common or more-natural English construction than is "of kind".)

In America, the scope of terms rebate and coupon is quite broad, and covers cash discounts as well as in-kind rebates and the "Buy 12, get 2 free" sort of promotion. Inducements can refer to free gift promotions, such as "Start an account now and get a toaster" or "Buy this car now and we'll wash it for a year".

A less-neutral term is lagniappe, "a small gift given to a customer by a merchant at the time of a purchase, such as a 13th beignet when buying a dozen, or more broadly something given or obtained gratuitously or by way of good measure; a bonus."

Among linguee translations are

• free of charge for promotional reasons
• promotions
• "free goods"
• rebate in kind
• proportionate quantity in relation to the delivered quantity
• voucher for ... natural discount
• inclusive bonus quantity ... inclusive free goods

I'm not sure how many people would accept it as an "English" word, but gratis - without reward or consideration. comes to mind.

The more familiar, complimentary is often used the same way. Note that this is an adjective. Actual items are normally named (e.g. - a hotel offers complimentary breakfast), or collectively referred to as complimentary gifts. From the "trader's" side, such things may also be called corporate/promotional/business gifts/products; the recipients are more likely to call them freebies (or goody bags, which can be much more than candies for kids).

Gratis is more likely to be found in legal contexts (where you also find pro bono, used to describe work lawyers do without direct payment).

Complimentary is mostly used in commercial contexts where a trader provides something free, usually complementing (going together with) something else you're paying for. Note the different spelling for complimentary (something nice said or given), which many people get mixed up (that's 420 written instances of "complementary breakfast" written in error).

Various retailer rewards programs give you a free gift periodically, simply for being a member.

By themselves, rebate or bonus don't have any immoral or indecent connotations. (Maybe it's the "in kind" part that the people you asked found objectionable.) However, they do imply that a previous transaction of some sort took place.

As you mentioned, free goods is usually used in the context of duty-free goods.

As suggested by FumbleFingers, something that's complimentary incurs no cost or obligation.

I think you have two options to resolve the issue. (That will put you in a new dilemma?)

First, find the reason for the 'something', rather than what are all the non-reasons for it. That will tell you what to call it naturally.

Alternately, call it simply a gift. 'Gift' does NOT have negative connotations of immorality, sexuality, or expectations in return, per se. After all, it's the thought that counts.

"token of our appreciation", as in, "Please accept this as a token of our appreciation." [e.g., for pointing out that bug in our software to us]

You could easily refer to the extra merchandise as a "free bonus".

For example: https://www.amazon.in/Face-Chilled-Bonus-Shampoo-Conditioner/dp/B01BQII0CE -- "Axe Face Wash, Chilled 5 Oz with Free Bonus Dual 2 in 1 Shampoo + Conditioner" (The product you buy comes with a sample of another product by the same manufacturer.)

https://www.amazon.com/Motions-Neutralizing-Shampoo-More-Bonus/dp/B0089NQ3BU -- "Motions Neutralizing Shampoo 25% More Free Bonus 20 Oz" -- the normal package is 16 ounces, but for a limited time you get 20 ounces for the same price.

https://www.usatoday.com/story/money/nation-now/2017/11/28/holiday-gift-card-roundup/900217001/ -- "Holiday bonus! Buy a gift card, get a freebie at these restaurants" -- as a temporary promotion, these stores give you an extra gift when you buy a card.

(Disclaimer: no connection with any of these sites or products, they are just what came up when I searched for real-world examples.)

Note that in some parts of the world there may be retail regulations that restrict the use of the word "free" when referring to something you only acquire by making a purchase of something else.

The legal word "boot" applies when the seller offers something extra, not required to fulfill the contract:

"When I purchased bath towels, the merchant gave me face cloths, to boot."

"The Ford dealer performed my 10,000-mile maintenance, and washed my car, to boot".

The boot is given as a courtesy, to cultivate customer loyalty. There is no connotation of immorality.

I'm not really seeing this addressed in the other responses: it's quite nonsense that "rebate" or "bonus" or any of these other terms would be taken to suggest anything immoral. These terms are common and normal in consumer and business contexts.

I'm guessing that in the German term, "rabatt" refers to the value being transferred and "natural" means it's product, not money, involved. To the extent that English "rebate" is the cognate of "rabatt", there may not be a one-to-one correspondence. "Rebate" is very common to mean a partial refund, post-sale, of the purchase price. We occasionally see some goods advertised with a "mail-in rebate" offer, in which the consumer sends a coupon to the manufacturer to claim a payment. Other rebates are at time of sale; however, they're usually calculated post-tax; if they're calculated on the sale price, they'd be called a "discount".

I don't think "rebate in kind" is in common use as "rebate" is always in reference to money.

"Bonus" normally means that you get extra product; for example, buy one, get one free; or a large amount being sold at the price of a smaller one.

In cases where product is supplied for free, especially to make up for a failure on the part of the merchant, the verb "to comp", from the sense of "complimentary" meaning free-of-charge, is common within some industries. As in, "the restaurant apologized for the delay in service, and comped us our desserts". In business-to-business transactions, it may be more common to offer to discount the next order.