Best OPK'S?

Jessica • TTC # 1
I've been using the clear blue digital but I've started testing twice a day and I'm running out of strips? What are the best cheapies I can buy. I don't have time to order online so I would prefer ones I can buy in the store. Should I just keep using the Clearblue? I don't mind spending the money but I would like to know if there is a better option?