Yes, transfers are a great way to produce small quantities of shirts without having money tied up into printed shirts, plus the added cost of screen setups, minimum orders on screen-printing, etc.
Transfers, like every process, will have it's limitations. If your art is very highly detailed, many colors, lots of halftones & fades, then a sublimation type transfer would be better, but then you're limited to white/lite shirts.
If your designs are simple art, a few colors, then a standard plasitol transfer will do OK. You'll need a really good heat press. One transfer company
M & M DESIGNS | HOME comes to mind, I'm sure other forum members will have others to recommend.
Another idea would be to find a
DTG printer on this forum, and sub out the work to them.