I have listed the recommended equipment required for both FOWLR and reef aquariums below. There are added items for a reef aquarium but the first section will apply to both.
Please note that this is only a recommended guide. You may do things differently but in order to run a saltwater aquarium, especially as a beginner, it will really help to have the equipment that will make things easier right from the start. You will also end up saving a lot of time which will therefore increase your chances of success, satisfaction and continuation in this great hobby.
Remember that if budget is an issue, you can always buy second hand/used saltwater aquariums from places like eBay and Craigslist and go from there.