I don't know there is any way to get really cheap single or two day Disney park passes unless you are part of a large group or convention, or a florida resident. Several years ago, we invested in multi-day non-expiration park hopper passes, and continue to use them for the one-off trips when we aren't staying long, since the per day cost was cheaper than a single day ticket.
We bought our passes on undercovertourist.com using the link in the Mousesavers newsletter that comes out on the 15th of every month.
The Mousesavers newsletter also includes lots of hotel deals for offsite hotels, that you might want to check out.
Cathleen
Mom to DS 8, DD 5 and a Greyhound Princess