The most expenses I have purchased was 2 x mini windows media box (atom/2gig ram/32 SSD). Priced at about 100US each.
Both machines worked out fine (using both on different tv's for netflix etc).
I would not buy android devices etc off there however.
Everything else has been screen protectors and phone cases and never had a problem with those, the screen protectors have saved me a couple of times.
I guess it really depends on what you buy, I just don't see the point in paying $40NZ for a screen protector when you can get the same glass screen protector from ali for under $5US.
Or $70 for a phone dock for my sony z3 when I can get them from ali for $10.
I am currently waiting on 1 x car camera that cost me under $20 US due to the app day they had
1 x iphone 6 battery case with a 7000mah battery
1 x nexus 5 battery case with 3000 or so mah battery
should be interesting to see how those turn out.