all good answers above. i primarily wade.
the answers to your questions depend on how you're going wade and what you value.
if you plan to wet wade in the summer i would recommend getting some columbia PFG pants or something similar. these will protect your legs a bit from poison ivy, sawgrass etc. on land and a little bit in the water from sticks, rocks etc. i would also recommend something a little sturdier than a gym shoe for foot protection. neoprene wading socks really help cushion.
if the stream you're wading is clean, clear, not too rocky, not too urban, you're not busting through brush you probably don't need all of the above.
as far as waders go i've had cabelas, simms and patagonia and one other but forget the brand. all of them purchased on sale. they will ALL leak eventually. so far i like my simms gore tex the best due ease of repair both at home or sending them in. the patagonias are new cause i couldn't get the simms repaired last year during the shut down so the jury is still out on longevity but initial eval is thumbs up.
you'll need to decide what kind of wading you plan to do now and in the future. if you don't plan to wade much with waders then get a cheap pair. if you think you'll be wading 5 years from now you may want to make an investment. also simms and patagonia have the most options in sizing, they are also the most expensive. i'm not saying an inexpensive won't last. it's been my experience that the gore tex from simms are pretty darn good. i get the 3 layer ones.
as far as boots go... it depends on what fits your foot best. definitely try the boots on with the waders as some you'll need to go up a size and others are sized for the neoprene bootie. most companies make a decent boot. the longest i had a pair of boots last is 3 years and that was with tlc and glue for the sole the last 6 months of their lives. the constant wetting and drying delaminates the sole from the boot it's all glued. altho patagonia just came out with a sweet looking boot that the sole is stitched so it can be replaced. pretty darn pricey tho. it could be worth it for someone. price per wear is good measure of a goods value.
again it all depends on what you are going to do with your gear and what you value.