if you are thinking about starting a t shirt business, do alot of research about what equipment
you will need a plotter cutter, you can get standard plotter cutters these days $230-$400 off ebay or a roland 1000-1500. depends on your price range if you want to start small and grow i recommened standard plotter cutters.
if you get a swing away heat press/ it will let you press onto t shirts/ jigsaws/ phone cases etc just beware that the plate goes from 12x15 / 15x15.
you can get a clam heat press whitch is just good for t shirts as the plate wont drop flat onto a jigsaw and phone cases but the plate size can be 38x38 / 40x50 whitch is a big differance just depends if you want to just do t shirts or grow into more things.
i would start with flex to start , i recommoned hot peel transfer as to cold, it will help the production of your items and if you need to muilty colour layer this will help you instead of waiting 2mins per colour to cool.
if your going to go into sublimation printing.
you will need a
ink jet printer i recommened epson1400, its a 6 cartridge ink set, so (cyan,magneta,black,yellow,light cyan,light magneta
dark transfer paper, you peel this then stick onto the t shirt and press.
light transfer paper, you put the tranfer onto the place you want the image and press and then peel off
the paper it will imbed the ink into the t shirt.
with the cheap transfer paper you will need to contour cut around the image or it will leave a white outline or a square around your image and look horrible, so if your going to do sublimation make sure when you buy a plotter you get optical eye.
hope this helps a little.