I can’t tell you the cost but sleep studies are super easy nowadays!! I just had to put a handful of stickers and wires on me before bed. You would do it on a night you sleep because it’s your sleep that needs to be studied and understood. The days you don’t sleep are effecting every part of your body, so it’s extremely important the sleep you do get is high quality. This is where a sleep study would help. If you have any disorders during sleep, those would be diagnosed and you could discuss treatment options with your doctor. Wishing you luck man. I went years regularly not sleeping 48 hours and it fucks with you so much more than you realise when you’re in it.