Can I claim first time home buyer if I bought the house for a small amount of cash and paid legal fees? What paperwork do I need to be approved?

CRA Says:

You can claim $5,000 for the purchase of a qualifying home in 2017 if both of the following apply:

• you or your spouse or common-law partner acquired a qualifying home; and
• you did not live in another home owned by you or your spouse or common-law partner in the year of acquisition or in any of the four preceding years (first-time home buyer).

You can find what a qualifying home is and more information here: 

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-re...