It looks like it is self adhesive with velcro, and that is great but what about all of the other tubes? Could you create enough for a full set? You might want to talk to a screen printer about branding them with the charity logo so that it gives people a memory for what they purchased.
By selling these items to donors, realize that the production value of the item is not a donation to charity and cannot be claimed on their taxes. Make sure that your receipt specifies the difference.
Lastly, with price you want to make it cover the cost of materials, shipping and handling, and extra money for the charity. Determine what the lowest price would be, and then tell people a number at least 25% higher.
I.E.
Materials $5.00
S&H $8.00 (USPS Priority)
Charity $2.00
tell people $25... and you can negotiate down to $15 if they balk at the price... but most people are willing to pay more for an item because they know the proceeds are going to a charity.
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Women think they're so clever because they can fake an orgasm for the sake of a relationship, but men can fake a whole relationship for the sake of an orgasm.