Bass traps - foam cushiony items from Amazon ok?

Foam is really not a good acoustic treatment.  Sure, it's cheap, but I have had weird results with foam.  The best acoustic panels are made from fiberglass strands or similar.  The cheapest of these are from GIK (or you can actually make them yourself from something like Owens 703 panels (just google for ATS Acoustics). 

For bass traps, you really need a very thick panel (like 12-14" or more).  Either that or tuned membrane bass traps such as the Scopus series from GIK Acoustics.  2-4" panels are not effective at bass frequencies.

Artnovion seems to have nice panels, a bit pricey. Much nicer looking than the lower priced items and hopefully much higher quality.

i just want to get a hint as to sound improvement by buying the cheap foam panels before spending big bucks.  I wasted alot by not going better in buying spkrs, upgrading speakers is a very costly path. 

No

Artnovion and Vicoustic have the most beautiful products to my eye. But they are not cheap. The best value often is provided by GIK, who will provide a treatment plan for a small fee, refundable on your first purchase. Like others, I recommend panels made of rockwool (and fabric covered), rather than foam. It is far more effective acoustically, and it does not oxidize and deteriorate over time, which some foam does.

@jumia you won't get a hint as to the sound improvement in your bass by purchasing cheap foam panels. You will gain zero information.

It would be analogous to attempting to find out what someone's voice sounds like from a speaker by using _only_ the tweeter—it would sound like that person was mute.

You must use the proper product to achieve your goal.