what are good ovulation sticks

Ali
Hi we are ttc in 35 1/2 and hubby is 39 no prior children for eaither of us.  I am using this app but I also bought sticks because my periods are so irregular I would use both app and sticks to determine when I am fertil. I paid 12.99 for 7 sticks and one preganancy test at target there brand but I want more than a 12 day supply I saw some on eBay but they are coming from China and I'm a little weary I don't want to spend a ton of money but I want at least. 50 day supply any suggestions 
Any