It also depends upon what size sheets you need. I chose 5052 because I could get 5' x 10' and 4' x 8' sheets. The thinnest I could get in a 5' x 10' sheet was 0.050". With the Trump trade wars, I paid $150 for the 5' x 10' and $75 for the 4' x 8'. I tried to wait the trade wars out, but my project had a trip it needed to be done for so I had to bite the bullet. The 5052 is supposed to be a bit more corrosion resistant. Seeing as this is my first build, I do not have much to compare it to.
If anyone needs an aluminum supplier in Sacramento, CA, check out
http://www.cardoindustries.com/ on El Camino Ave. It's a small mom/pop (well only pop in this case)
place that sells all types of aluminum stock. He had to order the 5' x 10' sheet but it only took two days, other sheets were in stock. Nice guy, he really helped me out with securing onto a small pickup without bending the sheets.
I know this is late to the show and you're probably already done. Just food for thought for other newbies like me prowling this forum.
Just my two cents and good luck.