Cheapest way to mount umbrella softbox reflector for Speedlight?

I bought 20″*28″ Umbrella Softbox Reflector for Speedlight (Model: 6Y19. Details & dimensions), assuming I can just mount it on my light stand. That was a mistake. I need this reflector softbox, for portraits and food photography.

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The problem:

The soft box just came with the box, diffuser fabric and 4 spikes as you can see in the details. So one end of the spikes sticks in a corner of a soft box but the other end has nowhere to stick in. In order to use this reflector softbox, I seem to have 2 options:

1. I purchase Bowen’s speedlight ring and Bowen’s adapter. But it seems like they’d cost ~$20.00 a piece, costing me extra $40 in total.

2. I could buy E27 Base socket for less than $20.00 – but then I’d have to be in the proximity of a power outlet.

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Question:

Is there a solution, which let’s me mount my manual flash and the softbox reflector on a light stand, and is also cost effective?

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EDIT
I have tripod and a light stand with cold shoe mount which I’m using for shoot through umbrellas.