I use several printing methods -- it just depends on the job.
For small runs of light shirts, or designs on lights with lots of colors, or photo based design on lights, I use
JPSS inkjet transfer paper for lights.
For small runs on dark shirts, jerseys, and accessories, I use custom cut vinyl.
For larger runs on shirts, and accessories (not nylon), I use plastisol transfers.
If you have the ability to do silk screening, you can make plastisol transfers. Those are made by silk screening (in mirror image) onto a special release paper. However, if you do have the ability to silk screen, then there really isn't any need for plastisol transfers, is there?
Sublimation printing is not a substitution for inkjet transfers, or
DTG printing because the garment must be 100% polyester.
As for your t-shirts or other garments, you many not have to purchase a large stock. Look for a vendor who does not require a minimum purchase.