Some background: I never keep a revolving balance on any of my credit cards.

I had no cash so I put all of the repairs and purchases on a 50k loan at 25% and 50k credit cards at 25%. 

With this income, I have finally balanced my credit card situation.

Can I use a credit card as a deposit?

Lease docs, contract docs for when our clients buy/sell houses, anything we need signed is done through there.Giving tenants the ability to pay online or with a card.

It has to be a cheaper way than just buying rolls of stamps for hundreds of post cards.

That means you have to put $1000s into marketing every month, put 30k miles on your car every year, talk with hundreds of people every month, hand out 100s if not 1000s of business cards just to get your name out there.

The 2nd issue is rents or monies pass due, if she signed it and did not pay it, then she is in breach of her lease.Personally I would move unalaterlly, file for unlawful detainer for the monies owed with late fees, and deal with her case, maybe see if the attorney can open a counter lawsuit for that case to try and force her to folder her cards. 

What about a business credit card.

Taking on $50K in credit card debt to go through a guru course isn't the same thing as a 30 year fixed rate mortgage of $100K on an income producing (hopefully, anyway) duplex.