Alright so something I can tell you about this because I do this in house IRL.
Alright here is a small investment if you can prove your designs will sell on cafepress well then this is the next real step that will allow you to make designs on multiple color shirts and sizes and not stock huge amounts of printed shirts.
PLASTISOL - The Essence Of Screen Printing
It is what is used in screen printing, its the ink that makes the design.
It's done in layers and not one fell swoop. So a design with four colors would be "color seperated" in a illustration program - corel draw or adobe illustrator ( corel draw is still the industry standard I hate it though) then these layers are done in order on a screen printing press, with "curing" (the setting of the Plastisol so it's dry and flexible ) of the layers being done with a flash unit after each layer. then once all layers finished they get cured again usually through conveyor belt flash unit.
NOW THAT SOUNDS LONG AND COMPLICATED RIGHT?
well it is and if you dont have the numbers to have your own equipment, nor want to stock that many shirts in every color and size and design, what is your option? Well there is something that is the perfect step in between.
PLASTISOL HEAT TRANSFERS - Gods Answer To The Tshirt NetPreneuer
These are the most awesome thing ever invented.
They are real screen printed designs, but they are done onto paper and a fixing agent applied to the back of the design. A heat press is used to apply them to almost any apparel item you can think of.
Now think:
You could have a catalog of 250 designs, and allow customers to buy that design on 6-15 dif types of apparel items. And only stock blanks.
As orders come in you set a time later in the day where you turn on the press and do that days orders.
In the morning the ups truck comes by and takes em away.
using your garage and some cheap labor and you have to do absolutely NADA yourself.
WHERE DO I GET BLANKS?
2 places I have used and still use are : Broder.com and Alphashirt.com
cheap in bulk, and watch them weekly for discounts.
get ready to show a tax id.
They carry american apparel which is the in thing right now and will up your sales a lot if you use them.
OK ---> I'll stop rambling cause honestly this is the wrong forum for this:
I'll start you off with a good thread where a guy that was doing only screen printing ordered a bunch of stuff from dif Plastisol Transfer suppliers, shows how the transfers turned out on actual garments.
JOIN THIS FORUM, people here have experience and really share information about the industry as a whole:
T-ShirtForums.com