I guess, I mean for 4000 stickers 3' x3' is $600+ vs $360 at psprint idk.
Take it from me friend. I got a good amount of stickers for an amazing price -- passed them out.
Got oh so many "can I have another sticker? mine looks terrible due to peeling, UV exposure, etc".
I'll pay out of pocket to make sure I get good reviews on everything I put out.
Here's another hint. A lot portion of your business is probably gonna come from personal referrals (conscious or not). So it's worth it.
IF the site doesn't seem to specialize in sticker, but is one of those "do-it-all" places. Go elsewhere, immediately. I've said it before and I'll say it again -- it's hard to do more than one thing good.