In the Top Bar Hive (TBH) the bees make their own wax, all of the other types of hive can use foundation, strips or let the bees build natural comb to the sizes they require - more natural…
Cost of buying foundation varies according to the quality, quantity, wired, un-wired, thickness, cell size and how much you want to use.
Bees making their own wax is said for every pound of Wax made, it takes 6-12lbs of Honey to produce.
Some Beeks give the bees a start and use foundation, some choose smaller or larger cell sizes if they want drone comb, large workers or small workers, as they beleive this may help with pests - unproven
You have to decide whether the first year you want healthy comb or lots of honey. Bees Building their own comb are said to be healthier.
Some wax from the suppliers is mixed old wax from other bee keepers and may harbour toxins