This is my first build.  PSA (magpul MOE enhanced  kit) APF lower.

Free float or not?

I say yes, free float.  It'll help out your accuracy a little and reduce POI shift from using barriers and shooting rests.  Also, a fixed FSB can really be annoying if youre planning on running optics of any kind.

Truthfully it's more preference than practicality, but IMO, FF is better when available.

That is the way I was leaning. What are some good options for parts kits to do this job?  I know PSA offers very low cost pre assembled uppers but.....
Better options out there still ar reasonable cost?  This will be a flattop with some MBUS pop up sights.
Also any suggestions as to free float handguards and all that is required to have a free floating barrel.

If youre looking at pre-assembled, PSA prices are hard to beat.  You could probably shave a few dollars by doing it yourself (depending on who has what in stock), but youd have to buy the tools and PSA would probably beat your build in quality.

Regarding handguards, you can pay a lot for a FF rail, or you can pay a little.  I've always done the latter ($40 FF rail and barrel nut on ebay) and I've never felt that it was inadequate.  IMO, the rail is a great place to save money.  However, the barrel is not.  Building it, you'd have more control over that, but buying pre-built, probably not.  Long story short, I'd do a PSA and be done.  Their prices really are crazy low , especially if you nab one of their deals