Stickers reward implementation? (Patreon)

I mentioned earlier this month I was gonna implement a new reward, telegram stickers. 400x400 px 300 dpi transparent png files. What prices would you consider adequate? Obviously the higher the tier the most detail and time will be invested (as 30 usd may even be bw stickers). This will help me get a media of what most of you consider my art would be worth in a sticker monthly. I may fuse them as part of existing tiers or create a brand new one just for stickers. I wanna hear your opinion, people <3