With $8.59 you can buy 10 vacuum/recharge valves. A little "silver solder" a vacuum pump, a gauge set and a can of freon, you can do it yourself. There's hundreds of "you-tube experts) to show you how to do it.
You can buy the valves on EBay:
https://www.ebay.com/itm/10x-Service...EAAOSwg3hfFwgF