Here is an example of how easy bento can be for someone who has only ever made the standard brown-bag sandwich lunch. I woke up late this morning and decided I only had time for a pretty boring lunch -- ham sandwich on a bun, grapes, cucumber, and some carrot sticks. I was tempted to just toss all this into a paper bag. Instead, I broke out the sandwich box and lined it with wax paper. I tucked in the sandwich, the put the carrot sticks in a cute little pink container (it's under the grapes). Grapes go in a pretty waxed paper cup to keep them from getting the sandwich soggy. Cucumber tucked in corner for same reason. And I put in some pasta spirals to fill the gaps and look festive.
See? It's all about presentation. Just use your normal everyday foods, probably smaller portions and more variety, tuck them into a cute container and you've made bento!