Dude. Fixing the AC wont do dick if you can't control the air doors correctly. A/C working or not, you can't defog without proper airflow. You say you want to fix it cheap, but are still putting money into the A/C.
Not using an AC machine, I would slowly add through the low side with one of those aftermarket fillers so as to NOT flood the compressor with liquid. Ambient temp, underhood temp and moisture in the air play a role in calculating pressures. WARM ENGINE, FAN ON HIGH, RECIRC DOOR OPEN at 60 degrees F, I would probably expect your high side pressure to be stable in the 150 psi range, with the low in the very low 30s. I might expect some cycling, but not much. Altering temps will alter those readings.