There's a new series of chinese 7" android tablets that appear to run pretty well in the various youtube videos i've seen online, but i haven't come across anyone that has used one with construct 2 games before.
They are only $65-$75. 7", 1.2ghz and run android 4.03
They go by the names Allwinner A13 7" android tablet on ebay and other various places online.
here's a review of one