A few years ago, Marvel Comics reprinted the first 50 issues of their original run as five trade paperback compilations, but they're long out of print and I think they command pretty hefty prices on the aftermarket.
However, IDW Publishing, who just secured the license, will be reprinting the Marvel series starting next year. It looks like it'll be the same format as Marvel was doing -- ten issues per volume. I assume they're doing it this way so as not to rile up those of us who bought those first five volumes and don't want to buy them again! The first two volumes are available
here and
here. They even use the same J. Scott Campbell cover art as the Marvel ones!
I just hope they realize and understand that sales may not be fantastic for the first five volumes since many fans already have the Marvel versions. I'm sure there will be a spike after the first five, when they start reprinting material that Marvel never got to. Plus, most fans tend to consider the 50s, 60s, and 70s the highlights of the entire series so I would expect sales for a 6th, 7th, and 8th volume at the very least to be pretty good, so I hope IDW will take all of this into consideration as they put this line out!