I'm sure you can get one there. Try aircon/ref supply stores (especially automotive aircon supplies). Aircon technicians use vacuum gauges.

Yes I got a vacuum gauge from Binondo. In aircon/ref supply they usually have that gauges that is also for pressure but a tiny bit of vacuum graduation when the needle goes down, its like 700 to 800pesos. But what I got is from Alonzo there is a store in there specializes in gauges. It cost me 350pesos, Taiwan made in mmHg. There is also China made but for 450pesos. There is also US made for 1200pesos. My degassing chamber works like a champ. I bought an empty freon tank cut it, with some hose gasket and 3/4" acrylic as a cover, it works like a champ.

What do you use to pump out the air?

We have equipment in the lab that does both pressure and vacuum so we hooked up the degassing chamber in there, But when we trouble shoot the chamber for leaks we went to local Auto Aircon repair shop, they have this vacuum pumps use to clean the car AC it also does the job.