Some parts stores do a free rental on specialty tools like that in the hopes you buy repair parts from them after. You leave a security deposit, take the tools, then get the deposit back when you safely return the tools.With that being said, would I need a leak down gauge ?
I only have $40 to work with at the moment, and in store prices are $70 and up on the leak down gauges in my area.
Do you need to do it at all? No/it depends. You could take apart more of the motor searching the source of the problem.
You could also just try to get it functioning as well as possible (but its never going to behave as an unbroken car would) and baby it as I said in one of the options, while planning for an eventual replacement motor.
Really it just depends if you care about figuring out why the compression failed, or decide to in the longer term just write off/replace the motor. To some degree poor performance and some drivability behavior issues are coming from that worn out motor.