If you've never heard of Aliexpress - it's a gigantic marketplace where you can get pretty much everything under the sun. The prices are usually cheaper than eBay/dealextreme/banggood too.
7% is a higher rate of cashback than usual for Aliexpress - and doesn't appear to be limited by category.
The current Topcashback referral signup deal also gives a $5 USD Amazon voucher after $10 USD cashback earned.
I bought a lightweight camping chair that is basically identical to the $124 AUD helinox chair one for about $30 AUD shipped (+7% Cashback).
Other items I noticed:
The 8bitdo SFC30 bluetooth SNES controller ($26 USD shipped) and adapter ($20 USD shipped) that lets it work with a NES. Supposedly these are lag free.
Fluke 17B+ multimeter ($100 US shipped). I got one from DX a while back and it is identical to the real deal - wouldn't trust the calibration statement however.
Optivisor clone ($16.30 USD shipped). Looks identical to the original that I have + you get all the magnification lenses.
USB microscope ($35.70 USD shipped) similar to the Andonstar Dave thought was ok on EEVblog.
Things to note:
Only purchases made on AliExpress's US site are eligible for cash back.
Please note that some merchants may not be forthcoming with untracked cash back. We endeavor to chase untracked cash back but reserve the right to halt inquiries at any time. Please do not make purchase decisions based on expected cash back as it is not guaranteed
SO basically they are admitting that some merchants on Ali Express may deny your cashback.