You do not "need" a sump, but when you have one, it's usually easier to control your water parameters.
As for lighting, unfortunately the Home Depot special will probably not work for you, other than help you grow lots of algae. There are some decent low cost lighting fixtures for beginners...take a look at
www.aquatraders.com as you might find something that works there for cheap. When you think about lighting, remember the less light, the more restricted you will be for what corals you can have.
Your best bet as a beginner is to come up with a plan, including tank description, livestock plans, equipment plans and then list them here for some of the experienced reefers to give you their suggestions.
Hope that helps.