i'm doing 120 level 3 units, finding it really difficult and have had to take a lot of unpaid time off so hasn't really worked out cheaper but given no choice by OU - they sometimes just decide they are going to change degree names and requirements which means you either have to finish quickly or pay to do additional modules. The problem is your grades will probably suffer (versus doing 1 or max 2 courses) and as you know OU grading is a level down compared to brick uni, so quite risky in my opinion. If doing again i'd only consider doing distance learning via a brick uni