If you're handy with a bench saw & a router etc you can make the brood boxes , bases & supers etc.etc. yourself for a fraction of the price of the big boys selling prices and make them in western red cedar to boot ( very long lasting wood ) ..
Thorne's & others sell metric or imperial sized " National bee hive " plans and several other sized plans as well so does the British Bee Keepers association (BBKA)
I made the vast majority of my own fifty national metric sized hives .
Having set standardized sized hives helps no end as all parts are interchangeable.
You'll only need one type of frame style , super or brood box etc.
I've taught keepers who had four or five different types of " car boot/auction " hives and all manner of hotchpotch devices to make incorrect frames sit in the supers & brood boxes.
They didn't do very well in the long term as they always had problems with things .
The only thing I got from Thornes in the end was the self spacing all wood Langstroth ( ? ) style frames & frame pins as I'd managed to get hold of a foundation moulding set at an auction for pennies .