Free: Contests & Raffles.
Sounds a bit risky. I'd stick to a proven style and not skimp on safety gear. Also, get those straps in your nether regions tight right off the get go. Worst case you take a fall and if things "cinch up" real quick you could end up hurt worse.
You can hunt 1000 times safely but only fall once.
I've used the ones that come with the stands, and have made my own for Mountain Climbing... That said they work, but they are not comfortable and you will go without to your own detriment. I spent the $120 on the nice mesh vest style after i almost fell out of my stand. The vests are cammo have good pockets and are easy to wear and get into and out of. Well worth it if you ask me.