is an $250 enrollment deposit tax deductible

It could be added to tuition and books costs for the American Opportunity Credit. 

Q. Is an $250 enrollment deposit tax deductible?

A. Yes, but only if you actually enroll. You can add it to your regular tuition and fees to claim the Education Credit. 

There a several things to be aware of:

1. There is no actual deduction. Instead, you use the qualified expenses paid to calculate and claim an education tax credit.

2. If you are your parent's dependent, they claim the credit, not you. 

3. Even if you are not a dependent, there are restrictions on a fulltime student, under 24, claiming the refundable portion of the American Opportunity credit (AOC). 

4. The AOC may only be claimed 4 times during your undergrad years. Don't waste one of those 4 times on a year with little expenses. 

Info on the education credits:

https://ttlc.intuit.com/questions/3383321-why-didn-t-i-get-a-credit-or-deduction-for-education-expen...

 https://www.irs.gov/Individuals/AOTC

https://www.irs.gov/newsroom/american-opportunity-tax-credit-questions-and-answers

https://www.irs.gov/credits-deductions/individuals/education-credits-questions-and-answers

 https://www.irs.gov/individuals/llc

https://ttlc.intuit.com/community/college-education/discussion/i-have-a-1098-t-form-that-i-received-from-my-school-and-i-entered-all-the-information-but-it-said-i/01/998249#M23054