If your starting from scratch - it's gonna take 6-8 weeks just to cycle the 30 gal.If you go with all dryrock possibly even longer which means your overhead expenses thru this period will be next to nothing if you so choose. We started w/ a 30 gal - 20lbs dry/base rock 10lbs Liverock and barebottomed. The liverock started the cycle and seeded the tank with coraline. We had a marineland powerhead + whisper filter pump w/ no media to move the water and a heater. Because we didn't want unwanted algae we didn't use a light at all thru cycling. Also we only topped off the water in the tank so as to let the gases generate healthy BB. We changed 10% of the water prior to adding the 1st fish (yellow tail damsel) and started using the lights 8 hours daily and then relaxed - let it cycle thru again. Point being, Slow is Good. You can throw tons of money at your new salty and the results will still be the same, the time factor doesn't change by much. So rich or poor you still gotta wait.
After this you have a Saltwater eco-system, you can add-on at your own pace. To start you will need heater, hydrometer, salt mix, some type of pump to move the water, ro/di or dechlorinated tap water, and a saltwater basic test kit. As for number crunching - go to the pet store either online or imperson and add it up. After your cycled thru the maintence isn't that much, changing like 5 gal a week costs like 2-3 bucks in salt.