creating something from nothing

I tend to have a very small crafting budget. Read $0. The few exceptions are for notions like thread that I use for none craft mending and sewing. Or glue Or water.
The rest of my crafting is often created form things I find at the recycle pad, or as gifts, or salvaged from something else.
Much of my fabric comes from give aways and salvage from old clothing.  scraps of wood, spray paint that was being thrown out. beads as gifts from those who were no longer beading...

So when I create something with the intent to sell it I struggle with how to value it. A few scraps of fabric a bit of thread and some empty plastic bottles costs me basically nothing. So I have go with time and how much is it worth?

Making bracelets that are colorful and funky and easy to make for almost nothing, but if I charge $1 I am only making $10 and hour. so if I charge $3 then I can offer a discount if someone buys 2. like $2/5
That ends up making them at about $25 an hour, which may seem a bit much but I do have to invest in marketing and such as well. So there I have justified the price.

The next question is how many to make. There will always be a percentage of them that do not sell and if the customer is making the choice I need to have lots of options. So for every 2 I sell I need 10 available maybe. I realize this is a problem because if I make 10 and only sell 2 I have only made $5 an hour for my work.  Or it just means I need to have 8 bracelets whose only job is to market the others so that becomes a whole hour of time. So with 2 hours of work in I will have 12 bracelets that might sell so that is $30 divided by 2 is $15 an hour for my work.

ok I will drive myself nuts.
I will have a booth with pieces worth $300 and pieces worth $3 and everything in between. I have to trust it is all worth every penny and every minute spent creating and selling. Even on a $0 budget.