Yeah, the prices are pretty rough even for the shirts. I'm pretty sure a blank shirt doesn't cost that much and the designs themselves are okay at best for most and what I'd expect to see in a Hot Topic, which would not charge $42 for their shirts.

Also looking again I feel like the Greymon puffer jacket would make more sense to be themed around Garurumon given the latter is a character I'd associate more with the cold and a warm coat than Greymon.
On a side note, I did just randomly find Teepublic is having a sale on all their stuff sitewide and it includes a lot of Guilmon shirts:
https://www.teepublic.com/t-shirts/guilmon