targethobby.com has some similar ones: http://www.targethobby.com/3ch-dsm-2-24g-surface-receiver-for-rc-car-rc-truck-rc-bugg-p-4162193.html
the ones I actually got had the "spektrum" sign on them and everything (like this one: http://www.targethobby.com/spectrum-ar500-sports-5-channel-dsm2-receiver-full-range-p-4162033.html)
I haven't had any problems with them - range goes further than I can see, quite small in size - generally the work quite well.
the problem with the original receivers (and the reason they are so expensive) is that the manufacturers rely heavily on the margins from their sales. they know most people have 1 TX but several models and therefore know that most of us will only purchase 1 TX - not a huge profit to be made, so the receivers pay the price.
my main problem with RX's is that I personally, really don't think they are worth it. I don't see the reasoning behind paying