Cheap and low maintenance? Hmmm.
Used freezer from Craigslist, a large one. -> New freezer from Home Depot or similar; see the link in my sig. Buy as large as you can possibly fit in your home without death from SWMBO. Excess space can always be used for storing non-beer drinks, yeast, hops, etc. I bought a 15 cu ft model that can hold 10 kegs and 20# of CO2, and I wish I'd gone even bigger. Watch HBF for deals, sign up for their newsletter.
Used CO2 tank from the same. -> Remains the same, but ensure it is an aluminum body with a current hydro stamp. Buy as big as you can fit, as most of the refill cost is labor. Ex: for me, 5# is $21 and 20# is $36. Maybe buy a spare tank or two -- I have a 20# and two 5#. When my buddies run out their 5# on their kegorators, we swap tanks temporarily. This saves them a 1 hr+ drive to refill. Keep an eye out for "420" and hydroponic posts on CraigsList, as these guys are always offloading them.
Generic housebrand regulator (anywhere, but Chi Company has good ones). -> Dual primary regulator. I prefer Taprite as a quality brand. Cornelius, Chudnow, etc. are house brand / economy brands, usually with controls that require a screwdriver to manipulate. Norgren seems to be the Cadillac of regulators, but I can't discern any appreciable differences over Taprite. If you don't want the primary hanging off the tank, then a high-pressure hose is required.
Used corny kegs, ball lock, as many as you can afford -> New kegs, AEB brand. They're the thickest and best built IMO.
Cheap beernuts, tailpieces. -> Replace with John Guest fittings. See below.
Collar made from scrap wood. -> Collar made from nice oak or other dense hardwood, stained with oil-base stain and sealed with 3-5 coats with quality water-base oil-modified polyurethane (wait for Sherwin Williams 40% off sale, happens 6x per yr). Insulate with at least 1" of sheet styrofoam insulation. Plan your faucet hole spacing so you can fit one faucet per keg, should you want to some day.
CO2 manifold -> Secondary regulator bank with MFL input, shutoffs with check valves, 30 psi gauges, and MFL outputs -- one secondary per keg that the freezer can fit. Ex: 10 kegs fit in the freezer? 10-way secondary bank. Recommend mounting brackets to attach to collar and gauge protector boots.
Faucets -> Stainless Perlicks. 525SS/630SS at a minimum (plain faucet), 575SS creamers if you're feeling adventurous. Maybe a 575PC if you just HAVE to have flow control. All-stainless shanks with 1/4" bore, long enough to pass through the wall of your keezer plus minimum 1" exposed. 4-1/8" is most common size. Perhaps you want to save space for a beer engine faucet or a Japanese style faucet or...?
Beer lines -> Accuflex BevSeal hoses, 3/16" ID. 10' - 20' per faucet. Birdman Brewing offers free shipping on 50' and 100' spools.