Are there no printing stores in América?

First of all, excuse my english and also my autocorrect is in spanish.

So browsing reddit i see a lot of t-shirts/posters / mugs, etc. with cool art and in the comments theres always people asking where to get them and the answer always seems to be some sort of dedicated store with really high prices. But i always ask myself " couldnt you just print it yourself?". Specially when the art is freely available online. Is it a copyright issue? Although ive seen this with free art toó.

I live in México and we have tons of printing places, you could have a really good quality póster for less than 100 pesos, which is like 5 bucks. We even have designated áreas in cities that have several printing stores and supplies.

So yeah, ive always wondered if theyre not as common in América or Europe for that matter.