I recommend aliexpress. They're very likely the same decals (a lot of sellers on Etsy buy them and resell them!), but much less expensive. They can take 2-6 weeks to arrive though. I got some I ordered a few weeks ago, and they're great.
I plan on doing this too. My nails are short tho...oh well.
I might just buy the jamberry ones and have the nail salon techs do it.