I have to second the suggestion of compact fluorescent bulbs and work-light reflectors.
I was in Home Depot recently, and they had the big reflectors (10.5"?, 'brooder' I think?) for ~$14, and 2 packs of 6500K 27 watt bulbs for ~$6. Strip off the clamp assembly and hang them from a conduit/copper pipe fixture (they had little wire loop hangers) or build some sort of box to set them in if you don't like the looks.
I'm almost certain this is the route I'll go for lighting, using CF bulbs gives you a lot of versatility, you can change the wattage, etc. very easily. This post is pretty much what convinced me:
I'd also suggest going low-tech. You won't need to spend the money on a CO2 set-up, lighting, or fertilizers. and go for a low-cost substrate, there are quite a few options here, depending on how much effort you are willing to put into it, what's common in your area, and what sort of plants and such you want to try.
As to plants, a lot of aquarium plants can grow emersed. easily available things like 'banana plants' and aponogetons can look pretty neat with floating leaves (banana), or flower spikes (aponogeton).
I think it's quite possible to do this on a $400 budget, especially if you are willing to do some building/tinkering