Workout plan that is low cost and can be done at home?
There are tons of free calisthenics routines that can be found over the internet. Here are a few of them :-
Baristi Beginners Workout
---> Can't do pull ups? Do a negative pull ups or incline pull ups/inverted rows.
---> Can't do dips? Do bench dips (either with foot on the floor or on another bench) or more close grip / normal push ups.
Buff Dude's Punisher Prison BW Workout
---> Can't do one arm push ups? Just do close grip / normal push ups
---> Can't do handstand press? Do pike push ups
---> Can't do L-Sits? Do planks or hanging leg raises, follow the set and seconds provided
Fortress Beginners Routine
---> Can't do pull ups? Do a negative pull ups or incline pull ups
---> Can't do a pistol squat? Do your normal squats
---> Can't do handstand hold? Do pike push ups
P.S Can't do regular push ups? Do knee push ups or wall push ups.
Next, your diet:-
First off, calculate your TDEE and increase your calorie intake by 200~500(this is known as caloric surplus). Next your protein intake should be 1g per lbs of bodyweight, where as your fat intake should be around 0.5 ~ 0.6g per lbs of bodyweight and the remaining can be used to fill up your carb intake, and your micronutrients(aka vitamins and minerals).
However, this is also highly debatable since there is no right or wrong answers. By that, what I mean is that you need to adjust your calorie(if necessary) to ensure you are losing weight.
Lastly, do note that it takes time to either build muscle. Do not get disheartened when don't see any result in the next few days, weeks, months.