My little bit of past experience.
I used to get Polo Shirts made up when we went away on motorbike weekends I would organise.
I would get a typical size logo on the front ( printed not embroided ) and a lot of text written on the back - ( like each persons name - up to 8 of us - with a tag like - "gutless sack can only do 250kph" or similar )
For 8-10 shirts it would work out at about $25-$30.00 a shirt.
So whoever is going to take this by the balls and get ot rolling should firstly go to a shirt place and check todays costs and options. I found that most these places were quite used to 'joe nobody's' walking in with small order requests ( back then )