Once you've searched and/or ordered stickers online you'll be bombarded with ads. That's not a bad thing!
If you are building a sticker business there will be times that it makes sense to outsource your product. I'm attaching an ad I received this morning from Sticky Brand for 100 2.5" brushed aluminum type stickers. This would be great if you had a client request 100 or more stickers with that look. Honestly, I wouldn't even invest in sticker paper to create that look because it's so random.
My point is - weigh the pros and cons before making vs. outsourcing.
If it is for yourself, I don't think you would want to be stuck with 100 stickers of just one image unless you were getting tons of orders for that image. Don't invest in inventory! (In my opinion)
But, if a client asked you to make 200, 3" stickers, think about:
Your time - at least 4 hours
Material - $0.50/page with laminate, ink for 4 stickers on 1 page
Downtime - printer jams
Reprints - cutting machine mangles cut and you have to re-do (trust me, it happens)
Laminate curls with humidity and add wrinkles in sticker paper, not fixable
So, for that client, if they are not on a rush deadline - source out the best sticker discounts, let them know you are ordering instead of making, have it shipped directly to them, which hopefully will be free. Have them pay upfront so you're not out of pocket. Add on 25% for design and your time.
There's always the danger that they may elect to order on their own so you'll need to step up your customer service. Make sure you are the point person with the outsourced company in case there are any errors and that you make everything right. Make sure your client knows the delivery time so they don't have unrealistic expectations.
Sorry for the long post!
Let me know if you have any questions!