I check prices daily. I learned that lesson the hardway. Also make sure to use a cash back credit card to make the purchases and perhaps have a friend set up an affiliate account and funnel purchases through there.
I've had a few products on eBay that I've been drop shipping with Amazon. They were doing well for a few days. Today I sold some more, but the price has since changed on Amazon and I made a loss on those products.
How do you guys avoid that?
https://chrome.google.com/webstore/detail/price-monitor-for-amazon/agbkbeleeoeojfddopbgcjanfhnndmjb
Wouldn't that be too obvious though? For example, if all the sales are coming from one account to the affiliate link. Surely Amazon would catch on quick and ban the accounts.