p.s. I'd also work up a list of the basic supplies you need, bring it in to your local janitorial supply houses and get prices. We started a janitorial supply company in addition to our cleaning business and that way we get about 40% off the retail prices. About $25 for a basic business license and it will save you tons of money. We buy our supplies through our supply company and then re-sell it to our cleaning business with a 1% markup.
44-gallon trashcan with casters.
mop bucket, wringer, mop handle and 3-4 mopheads to start, microfiber mops are great.
commercial vacuum, we like the Sanitaires, although in the beginning you can probably use your household vac. Sanitaires never die, we use the SC679J model, and for a hose vac you can't beat the Dysons. We don't use backpack vacs as they make your back hurt after 30 minutes!
get prices on 44-gallon liners and small liners for deskside trashcans, paper towels, TP, hand soap and toilet seat covers and then you can re-sell those supplies to your customers.
check out the Cleanfix Parrot floor scrubber for the best floor cleaning machine there is in our opinion, takes the place of a van-full of floor equipment and folds down so it fits in the trunk of a car.
window washing bucket, wash handle and squeegee.
This is just the beginning, of course, you'll also want sponges, cleaning rags, spray bottles, etc.
Most office buildings will have a janitor closet where you can store your equipment.