Preorder, Back In Stock ‑ STOQ

I've only been using this app for a few days after switching from another app which was very glitchy, but it has been wonderful so far. The support is excellent - I wanted to move my notify me button and it was done in minutes. I was able to transfer my data over and send out some notifications immediately. Within a couple of hours I already had a sale directly from that notification. The notifications send out automatically when a product is in stock, which saves a lot of time (I had to do that manually with the last app).