I bought a lot of stuff for my profession (cdl), can I get deductions for this?

[martin67william]

also aren't we allotted so much for every day we work?

[Coleen3]

Yes, it is probably deductible. No, there is no allotment unless you travel. There are per diems for persons who must travel for work.

To be deductible, a business expense must be both ordinary and necessary. So, if your mailbox rental is ordinary (common and accepted in your trade or business) and necessary (helpful and appropriate for your trade or business) you can claim it. 

An expense does not have to be indispensable to be considered necessary.

See the screen shot below.