just my suggestion, now ebay is complicated. you should never use your selling account for buying (just to get feedback). it maybe have bad impact for your selling account
Yes ebay will notice your activity and will therefore notice that you are quickly buying the cheapest items and leaving the same 2 word feedback while probably contacting the seller to "give me feedback please"! Just use it as you should and you won't get in trouble...
I have an ebook which teaches anyone to have positive feedback as low as $0,01. PM me if you are interested