I would stick with cheapy ones if our cycle is still all over the place as you'll waste a lot of the expensive ones otherwise. I found the cheapy ones, once you have worked them out, give you a few days warning of approaching OV as you can watch line getting darker and darker each day. You can afford to pee on a couple a day if you need to to get an idea what's going on. But 2 cycles off the pill isn't long - give your cycle a chance to even itself out.
My other bit of advice would be (and I don't know how helpful saying this is) try to chill out about the whole TTC thing. You can drive yourself mad extremely easily. Unfortunately you (we all) have to accept that TTC is something that is largely outside of our control and no amount of opks and thermometers is going to change that a huge amount!
Hi there, I am ttc dc2 and have been using opks to pinpoint ov as I have irregular cycles due to BF. I have used cheapy ones and CB and have to agree with quodlibet. Both have worked for me but as it is a good idea to test 2 times a day it is a lot cheaper to stick with the amazon ones for the most part. I use the cheapy ones in combination with the cb test sticks. I get some warning pre-ov so I use the cheapys in the lead up then as I think it's getting closer I combine them. As the poster above says, 2 cycles isn't long so your body needs time to adjust but keep dtd when you can throughout your cycle as I heard on the fertility week they had on the This Morning programme that the body goes through a fertility surge coming of the pill. Good luck!