I think you'll end up paying for what you want, unless you find an open source or non-US developer. GPS plus high res graphics are a bit of a security risk, and I don't think it is a coincidence that its hard to find utilities that could make GPS targeting easy. Even freeware utilities could be subject to US export controls.
If you plan on doing any private flying, just bite the bullet, get foreflight, and drop a grand or so on the GPS/transponder brick that gets you GPS, ADS-B-in, plus weather. Everyone I know that has one of those setups says its worth it if you do any private flying.
Maybe check out prosumer-level UAV/drone/quadcopter forums and see what those guys are using. Some of them are getting VERY precise results. For example, they're good enough to do volumetric estimates of rockpiles and haystacks on farmer fields after overflight mapping, which would require less than 1-meter accuracy.
USAF UPT bases use a mapping solution for low level planning, and I think the license actually allows installation on a single home computer. At least it used to, since I remember taking a CD home and putting it on my computer at home about 12 yrs ago. So... consider seeing if your nav planning shop could contact the library at, say, 80FTW at Sheppard AFB, and see if the license is portable.