Relationships, business or personal, begin to fail when one of the partners feels unappreciated.
Discounts and commissions are sometimes a part of business relationships, but never should they be the only thing, or even the primary thing, that holds them together.
Retailers and designers want:
No hassles with their customers
No calls about stains, soil, and possibly the suitability of what they sold or recommended
Repeat business with their client
They don't want:
To feel like they have to be a cleaning expert
To apologize for the type of carpet or fabric they sold or recommended
THEY REALLY DON'T WANT:
To apologize for a bad cleaning job
To apologize for an unreliable cleaner
To apologize for a rude cleaner
To apologize for any other embarrassment or inconvenience caused by such a cleaner.
They don't really need:
A commission. If they ask for something, its ok to work out something fair. But its rarely important to the best of these people. Think of the bookkeeping nightmare that lots of small checks can be for such people.
Mostly, they should feel:
Confident in you to keep your promises and not embarrass them
Appreciated enough by you that an appropriate gift is given or service is given from time to time. Such gifts are important even if a commission structure exists. Flowers, expensive chocolate, good liquor, etc all mean more to such people than a few dollars for every cleaning job.
With the bosses permission, pastries and good coffee are nice touches for supportive sales staff. But never make yourself a nuisance or an interuption of business. And always make any such gifts expression of thanks, not bribes.