Avoid the FB ads. These are typically companies charging $40 for the same quality jerseys you can get on eBay/Amazon for $15.
The $15 eBay/Amazon jerseys aren't bad. I've sourced several for company logowear and the fabric/stitching/etc. are all good quality. They are typically a polyester wicking fabric with little stretch (easier to do sublimation printing on), similar to pro-level jerseys of the late 'oughts (vs. the stretchy, body-hugging, longer sleeved fits pros use today).
Some vids to watch:
https://www.youtube.com/watch?v=2F6KoC26NNc https://www.youtube.com/watch?v=X4Q5WfVlGtw If you want actual higher end jerseys online, two options come to mind: eBay and Le Col.
eBay: Lots of auctions where folks are selling unused kit. I managed to get a new-with-tags kit from the Colavita team (Castelli jersey and bibs) for $65 last year!
LeCol.cc: They sell top-end kit factory direct. You can always find a $60 off $120 coupon either via email or by completing a ridiculously easy Strava challenge (ex. work out for 5hrs during August).
ECMGN Therapy Silicon Valley: Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)