The big platform pedals with clips, like the Crank Brothers Mallet, look good in theory, but I found that the "clipless" part of the pedal stuck up and annoyed the heck out of me when I rode in regular shoes. The Shimano pedals with the clipless part only on one side annoyed the heck out of me for a different reason - half the time the pedal would be on the wrong side when starting from a stop.

For myself, I decided that I had to commit to either clipless or not clipless. So my commuter bike has BMX platform pedals so I don't have to wear bike shoes and my mountain bike has Eggbeaters. I can't imagine mountain biking without clipless anymore - the control is so much better.

Bike shops are marginal businesses at best. You can ask for a discount, but I wouldn't expect to get one. My suggestion is to buy the pedals online where you can get the best deal (keep in mind shipping costs though) and buy the shoes at your LBS where you can try them on.