There are some budget friendly ovulation tests on eBay in a good quantity for about 5-10$. You don’t need to buy the expensive ones especially when ttc for long time and your finances aren’t that great!
have you tried temping? i know it can be stressful and time consuming, BUT all you need is a Basil body temp thermometer and a fertility app with the chart. its the most accurate way of knowing when you body ovulates and you don't have to keep buying tests every month.
You can use FF or this app to temp...but I got some SUPER cheap ovulation tests on Amazon and I was able to conceive in 3 months, which makes me think that they're probably quite accurate....They may have been 5-10 dollars.