A.L.
I probably buy 90% of purchases that aren't groceries online: toys, shoes, clothes, home improvement stuff.... you name it.
But I think long and hard before buying anything from a small website - there are just too many scammers out there. I would much prefer buying things through a secure website like Amazon.
If your shopping cart does not working correctly, your site is cumbersome to use or if it doesn't look professional I probably would not order anything.
So no, it would not turn me off from buying your products at all.