Most decent flatbed scanners today will give you all the detail and image quality you need.
Im sure all you artist either use tablets or scan to get your art work to edit on corel or adobe or whatever your using at that matter. N00b question but would i be better off buying a scanner rather than a tablet.. trying not to break the bank. Is it possible to get a good scanner that will scan with high enough quality
Tablets can take some getting used to, but especially in situations where there is alot of repeat actions, they work great for keeping the carpal tunnel stress down. I have used a trackball for about 20 years and my thumb is getting pretty wrecked, so I bought a tablet. The tablet is not as helpful if you do a bunch of text and graphics at the same time (because of picking up/putting down the pen) but manipulating points and using the pen tool is alot easier. I have and use both, but your mileage may vary.Scanners nowadays are dirt cheap, and most of them do fairly decent job. Make sure to keep the glass bed clean. When it comes to t-shirts, in most cases you would not need anything higher than 300-600 dpi.
Tablets are great tools, but it takes time to get used to them, and for some artists they would never replace conventional media.
The best option - to have both (you can get either for under $100) and use them where they fit best.
The same also true for many of the Adobe apps ...The thing about a tablet (depending upon which kind) is that you can use the pressure sensitive feature of Painter X to make the angle, force and direction of the stroke effect the look in much the same way organic media would.