tips for gift vouchers or t-shirt stores?

[Andreas Nilsson <lists andreasn se>]

Hi!
Currently the foundation spend quite some money and most of all effort 
on sending gifts to all our Friends of GNOME donors.
If we would be able to replace the manual labour and postage with 
something like gift vouchers for GNOME swag, or sending t-shirts via 
some online store it would be a win.
Anyone in the foundation that have experience with something like that? 
Any good tips for stores to use?
- Andreas