Need a shipping box for Technics SL-1200-MKII

do what what abucktwoeighty says .

I wouldn't trust UPS to pack a table. The tonearm needs removed (cartridge first). Then, the dust cover needs removed and packed separately. If the platter comes out, that should get pulled.
Now, UPS or any monkey can pack it all up safely. Keep in mind that packing and shipping the arm and cartridge takes a little care. A broken needle will ruin all. Once you get it there, you do know that setting it back up will take some skill.

Go to mrboxonline.com. They will custom make any size box at a reasonable price and send it to you. They also have packing materials.
I purchased made-to-order double boxes and styrofoam sheets from them to pack & ship a pair of Dunlavy IV-A speakers to England. Nice price and nice people. (Fortunately, for me, they are local and I could pick up the boxes.)

UPS store will charge arm and leg. DJ Odissey box you can get used $25.

I highly recommend double boxing the unit. Try to find a box somewhere, like perhaps from behind Best Buy or similar. Then grab a couple other boxes so you can cut them and line the main box with a double layer. Maybe even triple layer. Use a box cutter or razor blade, cut the boxes so you can slip inside the main box on all 6 sides. We ship aerospace parts this way and it works great. Your new used box will be super strong.
Good luck, John