Living with someone who pays all of the rent but I am fully responsible for myself, and personal bills (work full Time). Are they entitled to any “living expense” credit?

There is no such thing as a "living expense" credit. However there is a dependent credit that may be claimed for you if the certain requirements are met. If you earned less than $4050 in 2017 and you meet all the other requirements, you may qualify to be claimed as a qualifying relatives. 

Who qualifies as a dependent?

The IRS rules for qualifying dependents cover just about every conceivable situation, from housekeepers to emancipated offspring.

Fortunately, most of us live simpler lives. The basic rules will cover almost everyone. Here’s how it all breaks down.

There are two types of dependents, each subject to different rules:

• A qualifying child
• A qualifying relative

For both types of dependents, you’ll need to answer the following questions to determine if you can claim them.

• Are they a citizen or resident? The person must be a U.S. citizen, a U.S. national, a U.S. resident, or a resident of Canada or Mexico. Many people wonder if they can claim a foreign-exchange student who temporarily lives with them. The answer is maybe, but only if they meet this requirement.
• Are you the only person claiming them as a dependent? You can’t claim someone who takes a personal exemption for himself or claims another dependent on his own tax form.
• Are they filing a joint return? You cannot claim someone who is married and files a joint tax return. Say you support your married teenaged son: If he files a joint return with his spouse, you can’t claim him as a dependent.