This is what I did back in 2009. I had suspicions, but didn't want to plunk down money for a recording oximeter that I might or might not need.
In the image below, the top half is a graphical representation of about an hour of sleep time of mine. The horizontal axis is time, the vertical axis is decibels. This comes from a freeware program called Expstudio Audio Editor (not sure if this exact program is still available, but there are plenty of fish in the sea).
The bottom half of the image is a zoomed-in portion (about 6 minutes worth). Listening to this portion of the recording, what you would hear is 20-30 seconds of silence, and then an explosive outbreath followed by a couple more breaths, and then the silence again for 20-30 seconds, followed by...you get the picture. So these are individual apneas.

And using this I was able to observe what was going on quite clearly, and then had the confidence to make an appointment with a sleep doctor to move forward with the sleep study and whatnot.
All this cost was the few dollars needed to get a microphone to plug into my desktop. Which nowadays come included on PCs and laptops.
Paul J.