Langstroth hives outside dimension are 16 1/4 wide, 19 7 /8 long. Made up of standard 3/4 material, this leaves an inside the hive dimension of 14 3/4 x 18 3/8. The 18 3/8 is critical, as it prevents burr comb from locking frames to hive. If you are using thinner dimension hive stock -- 5/8 fence board, 1/2 plywood, etc. You have to shrink the overall dimension to keep the inner length of the frame in tolerance. On 5/8 material you lose 1/8 at each end, or a total of 1/4. Shrinking the length a strong 1/8 , i.e. 19 5/8++ to 19 3/4 overall works fine.
You would be better picking up aluminum cans to earn money to buy frames than to try and make them to save a buck. Unless you have a fully tooled woodshop, making standard frames is a nightmare. I have done it with just hand-tools, but it is slow and painstaking.
I make frames by surfacing a 2x6 pine board to 1 3/8 thickness (ie take a 1/8 off), I then rip the surfaced board to 3/8 strips. Cut the strips to length (9 1/8). Gang up all the pieces with a clamp, and dado the upper an lower notches. The relief cut on the sides can be done with a hand plane on the ganged pieces.
The top bar has multiple dado's and rabbets cut. Ganging pieces works as well.