I signed up for printmojo and I was checking out the website, I know it might be a good deal to sell tshirts, specially because they can ship them for ya, but their trick is when you buy the blank tshirts, you have to pay before people buy them
I don't know the answer to that question. Err.. Which question? I guess a suitable response would be, thanks for letting us know.
Places that print per shirt order basis are normally a lot higher. You can check out http://www.cafepress.com I haven't seen any place that I really like yet. Basically if your only selling a few tshirts at a time you should use a place like that. If you are selling a lot of one style then economically it makes sense to buy them in bulk upfront. You just have to figure out your goals. If anyone has any good companies they've dealt with in the past I'd be intersted.