I'm not usually one for expensive kitchen gadgets. My husband, however, thought I should have a mandoline slicer and bought me one for my birthday a few years ago. He got me the De Buyer Pro-V Mandoline V Professionelle, which retails for around $230.00. It came with a carrying case, two horizontal slicing blades (one flat and one ridged), and three different sized julienne blades.
This is an item that I thought I'd never use. That all changed when I realized just how great it is. It saves time, creates perfectly even slices, and multi-tasks. You can cut not only slices of varying thickness, but you can make waffle cuts, ridged cuts, and juliennes with precision.
There are other models out there for a lot less money, and I'm sure you can find a decent one for around fifty bucks.