I voted just grain and a batch of beer for me costs anywhere between $25-$35, but the beer you end up with just can't be compared to normal commercial beer.
If you compare something like Little Creatures PA $20 a six pack it's still pretty good value. Alas I don't make beer to save money but make beer that you can't readily buy. It's my hobby and keeps me out of mischief (well mostly).
Just regarding the gravity (FG) I have beers brewed with US56 that have gotten down to 1.008 (mashed at lower temps) but many finish at 1.015; why? Because for me it relates to the mash temperature, the higher the mash temp, the higher the final gravity, as the higher mash temps provide more body as the sugars can't be completely consumed by the yeast.
With kits the FG will vary depending upon the amount of unfermentables that are in your recipe (eg. maltodextrine).
Don't be too concerned if the FG doesn't drop below 1.015 so long as it is constant and fermentation is complete you be sweet!
Cheers
AC
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