You could probably knock simple t-shirts out at an affordable retail price doing runs of maybe 50-100.
Mine, for example - on a 100 run with
IndigoClothing - would use 3 colours (red, yellow, orange - I think) across 5 placements and 4 designs. So I'd probably need 12 screens (at £20 a screen) - meaning a £240 one-time setup. Add in £180 labour, £175 for cheap shirt, a few bucks for postage and tax and ****.....
So around £700 for 100 shirts. Meaning £7 piece? Damn. That's pretty cheap. I thought it'd be more than that. And the setup is a one-time thing. So repeat orders just use the old screens. And your designs would only need like 4 screens, meaning £80 setup. So they'd be more like £5 each.
This might actually be worth doing, y'know....
You could even get small stuff embroidered for not much. If you were aiming for a retail of say £10 per shirt, you could do some kickass stuff.