I just weighed one right now and it was 21 grams. Though the weight would differ slightly based on the sigil, and more importantly infill percentage. I think the one I weighed was 20% infill.
I have several sets for sale on my Etsy page (link in description), so if your place nearby gives you a quote similar to my price, consider supporting the creator! I get people want to find the best deal, though :)