When it comes to storing single-issue floppy comic books, my preferred products are MyLites 2s and Half-Backs by
E. Gerber. Unfortunately E. Gerber doesn't have a way to order online so you have to actually call on the phone to place your order. The advantage of mylar bags is that they are both long-term archival safe *and* they look great; a comic in a mylar bag looks better than one in a normal poly bag. But E. Gerber's Half-Backs and Full-Backs are even more important: they're not only acid-free but pH buffered to last indefinitely and actually slow the deterioration of your comic. Normal backing boards (even ones labeled "acid free" or "archival") will become acidic over time, start to turn yellow, and will end up causing your comics to degrade more rapidly.
Since you only have ~30, I would recommend
50 MyLites 2s for "standard comics" (725M2) and then
50 "Full-Back" boards for standard comics (item 700FB). The total cost for 50 of each is only $21 + shipping.
(I know I said I use Half-Backs but I'm recommending you use Full-Backs because the smallest order of Half-Backs you can get is 100!)
BUT NEMOIDE, YOU ASK, WHAT DO I PUT *THOSE* IN!??
These plastic boxes should do the job nicely. They're sturdy even though they're simple, I think they look much nicer than cardboard. I use similar boxes to hold my laserdiscs and records and have yet to have any issues from them.
ONE MORE THING:
When you put your comics and boards in the bag, DON'T TAPE THE FLAP SHUT. Just fold it over. I've damaged comics while removing them from a taped bag and it's awful. The tape is useful if you're running a business and don't want random people flipping through your books, but otherwise I think it's more trouble than it's worth.