I think spending a lot of money up front on unproven (no sales or demand) designs is crazy not matter yoru budget. I would suggest you look at to options:
1) Find a Direct to garment (
DTG) printer in your area that can do a few shirts for you to show around. A
DTG printer can print only one shirt of each design if you wish. Go with the designs you think are most promising.
2) Purchase a heat press and have the designs done with plastisol transfers. You can buy the transfers in volume which would reduce your costs for that part of the process and then print/press your own shirts as you need to.
After 3 posts you can post a Service needed in the forum classifieds and perhaps somebody can help you with the
DTG shirts.
Good luck with your shirts