The cheapest bird bath that actually works is a terracotta plant saucer set on an upturned clay pot. At street prices the whole build lands under fifteen dollars, and birds use it as readily as anything sold in a store as a bird bath.
What matters is not the container. It is the depth, the surface, and the height.
The three numbers that decide whether birds use it
Water depth should sit at half an inch near the edge and no more than two inches in the middle. Songbirds wade, they do not swim, and anything deeper reads as a hazard.
The surface has to be rough enough to grip wet feet. Glazed ceramic and smooth plastic are slippery, so lay in a shallow layer of pea gravel or one flat rock.
Two to three feet of height suits most yards, though a ground-level basin pulls in robins and towhees. The same sightline logic applies to feeders, which is covered in where to hang a bird feeder.
Build options that cost almost nothing
A 14-inch terracotta saucer on a stack of two clay pots is the classic. Run a bead of silicone between saucer and pot so a heavy bird landing on the rim cannot tip the whole thing.
An old metal trash can lid works if you prop it level in a ring of bricks. A wide ceramic dish from a thrift shop does the same job for a couple of dollars.
Skip any container that held paint, fertilizer, or engine fluid, no matter how well you scrub it.
Placement and shade
Put the bath eight to ten feet from cover. That is close enough for birds to escape a hawk and far enough that a cat cannot ambush from inside the shrub.
Partial shade slows algae and keeps the water from cooking in July. A bath directly under a busy feeder is a mistake, because seed hulls and droppings foul it within a day.
Keeping it clean without chemicals
Dump and refill every two days in summer. Scrub weekly with a stiff brush, and use a nine parts water to one part vinegar mix rather than bleach, since songbirds drink from it.
Moving water roughly doubles your visitor count. A solar bubbler or a slow drip from a hung bottle is enough, and it stops mosquitoes breeding. The picks in best bird baths cover which pumps earn their price.
Winter is the one place a homemade build struggles. Terracotta cracks when trapped water freezes and expands, so drain it in a hard frost or switch to one of the heated bird baths designed for it.
