Jonna,
Totally agree with you. I was on ebay the other day and I have sold a few tees on there but I have seen tshirts going for 99p printed, just madness. My minimum price for a tshirt is £7.50 which is not a lot of profit, vinyl is a bit more expensive due to, like you said, weeding and time etc. People want everything for nothing these days, it's all well and good cutting your costs to sell but at the same time a profit needs to be made, thats why I do it and because I also love doing it.