Rocks to line garden beds (Searsmont, ME)

Hi, 2 broke USAF Vets here, looking for rocks to continue lining our garden beds...flower & veggies. Not real picky about size, just not too big for one of us to lift! Don't need real small ones - I grow a crop of those each year! LOL! "Ideally" 3-4 inches thick. One side flattish is perfect but not necessary. Width and length not so important. Flat rocks also welcome to make the next layer on the borders or to use as stepping stones. 3rd photo shows rock we dug out of driveway - way too heavy to lift! We can pickup within 20 miles or so, or you can drop off.