As per the details provided by you, it appears that you are planning to buy a Car with an intention to resell it later at a profit. In such a case the amount of profit made by you will be taxed under the head Income from Other Sources and will be charged to tax as per your slab rate.
If your intention is to keep buying such cars and sell them, then it will be taxed under the head Business & Profession.
Trust this clarifies your query.
Please feel free to call/ get back in case of any further clarifications.
Rohit R Sharma
BCOM, ACA, LLB-GEN, CERT. FAFP