There are a lot of ornamental flowers that are also useful and not too expensive en masse. Alyssum is lovely, a well-behaved groundcover, nice for bees, and marginally edible. Breadseed poppies produce massive amounts of seed to spread in future years. (Technically, yes, they're opium poppies, so YLLEEMV - Your Local Law Enforcement Environment May Vary.) Hollyhocks (all the malva, alcea, etc., variants) also produce tons of seeds - I've been collecting them from the weedy versions rampant through my city - and they're edible and very old-fashioned-pretty.
I had wood-sided raised beds that worked ok, but weeds wanted to lurk in the edges. This year I'm trying just humped-up dirt beds, paths are dug a bit down, covered in cardboard and then wood chips (and all the leaf mulch that blew off the beds over winter - Sigh). I'm growing out ornamental dandelions to hold the sides in, and have some Corsican mint as well. We'll see how it goes.
Paths are a pain. Well-trimmed grass looks lovely, but my grass wants to invade everything within reach. As always, wood chips are great if you can get them in quantity. (I can't, sigh.) Gravel has to be picked clean of organic matter to look tidy. Jay mentioned glass, and I want to shout out to one of my favorite businesses in Seattle - https://bedrockindustries.com/
- who do gorgeous recycled glass tiles and tumbled glass chips for paths. BUT I could never afford to do even my 2 small paths in their glass chips. And you have to pick them clean too.