B.Tech public relations

Yes, you can definitely do BTech course with 50% marks in PCM subjects, as many colleges accept 45%–50% PCM marks for admission. 
Some colleges even give direct admission or admission through entrance exams like JEE, CUET, etc. Given below are some of the top BTech colleges in India accepting admission on 50% marks with their tuition fees and placement package -

Source: The above information has been taken from the official site and may vary.

In short, if you want a BTech degree where food and lodging are included in a budget, it is best to look for a Government-Aided or State University campus.
• Government-Aided Colleges such as CET, JNTUA, TCE subsidizes the tuition and hostel rent, so your total costs over a 4-year period will probably be well within or even below your 8 Lacs budget limit.
• Private Universities such as Kalasalingam or SIMTS have tuition that fits your budget, but hostel and food are considered “services” and are expensive. If you want to keep your costs to 8 lakhs, you will need to opt for the cheapest rooms available, typically non-AC, multi-sharing rooms, and skip all optional campus facilities.