I've been interested in these, the prices vary wildly and they look virtually the same. There's a few on Amazon for $20-25 but they ship from China and take 4-6 weeks for delivery. Most of the bad reviews seem to be people not figuring out how to inflate them. And the occassional torn seam.

The cheapest offered with Prime is $30 https://www.amazon.com/gp/product/B01ERRG8MA/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A1I54URR6J5STU

or

https://www.amazon.com/Fontic-Convenient-Inflatable-Compression-Travelling/dp/B01EWU0DNM/ref=sr_1_4?s=outdoor-recreation&rps=1&ie=UTF8&qid=1466540065&sr=1-4&keywords=Inflatable+Lounger&refinements=p_36%3A100-3500%2Cp_85%3A2470955011