Maybe $200-$250. Get a T5 light. For chemicals, the rule of thumb is don't dose unless you can test for it. Your salt will have most of the things that may need buffered. Skip the live sand and get dry aragonite. Get maybe 3-5lbs. of live rock and 8-10lbs. of base rock. Don't forget a powerhead or two, a koralia nano would work just fine. Test kit, Refractometer, buckets to mix new saltwater in, algae scraper, thermometer, and a heater (2 would be better just in case one fails) are some other things you will need.
Basically, it's not the equipment thats expensive, it's the livestock.
Sorry.....post is kinda random and all over the place.