There is an app for IOS or Android, onXmaps Hunt. Basemaps I believe are free, or for $30 a year you can get your state complete with land ownership information, and a bunch of other stuff. I don't know if they have MGRS on their maps or not.
hunt gps
Basic Topomaps 7.5 minute or 15 minute series maps are free to download from the USGS site.
usgs maps
As near as I can figure it, if you go to the national maps download center linked on the USGS site, you get topo lines overlayed on a photographic base. Nice, but larger files - close to 25MB.
If you go to the historic maps link, that has top maps up through 2006 in the traditional topo map format, much smaller files. - 10- 11MB.
I have a 24x36 plotter, so I just download them and print them if I need to. Otherwise you'd have to mail them to kinkos or someplace to print them full size.