Hi
Normally it's an all inclusive price. This is better as you can Use the right things and you control the stock , if you rely on office managers you will get a tin of polish and a dish rag once a year.
Office cleaning kit isn't expensive though , if you microfibre it's a couple of cloths and a bucket cap full of mpc or similar . Maybe a trigger with an antibacterial for the toilets.
Couple of black/ white bags. It's pennies.
Hard floors are different eg pubs etc. lots of mops and floor chems starts to add up.
The margins are squeezed though as suggested and unless you go for more you can't make one job pay, unless you do it yourself.
John