Well, lots of folks here have more experience with different setups, but I'll offer my limited experience, FWIW. I had SR-80s & loved em -- only sold em when I got the HF-1s. I have used them with three entry-level portable amps:
(1) Super Mini Moy (now called the Mini Head) by Shellbrook Labs. [You will be advised by many here to do a search on the feedback for this manufacturer; I have nothing to add, as I bought my amp second-hand -- its quality was excellent, the sound signature was not to my taste, however.]
(2) Little Dot Micro.
(3) Portaphile V2 (not the newer V2 squared, called V2^2).
(4) I have also used the Little Dot Micro, but it's not portable.
Of the 3 portable amps, the Portpaphile stands head and shoulders above the other two. I suppose there's no surprise there, based solely on price. But it's a nice match with the Grado sound, and it's the one amp of those three I've kept as my portable (and sometimes home) solution. It also matches nicely with my Senn HD-580s and Ety ER-6is. I usually use the Little Dot Micro at my desk, but I'm switching back to the Portaphile more often even when stationary, as the LDII is sounding weird lately & I'm re-acquiring an appreciation for the Portaphile.
Another thought, though: The SR-80s don't really NEED to be amped. Don't get me wrong, they do improve somewhat with a good amp, in the bass response and in the overall definition throughout the spectrum. But the improvement is not overwhelming. I think that's because they are designed to work very well out of the box with a variety of sources, without an amp being necessary. (I can't say the same about the HF-1s, which really seem to need an amp to shine.)
So, my recommendation is: Enjoy the SR-80s without an amp for a while. Then, when you want to spring for an amp, get a moderately decent one, not an entry-level model. (I'm counting the Portaphile in the moderately decent camp, and I think there are others here who would agree.) Don't waste your time or money buying a low-end amp for the SR-80s -- they don't need it & you won't get much out of it.
Just my opinion. YMMV.
Tom