1
I don’t have very free time.
I don’t have much free time.
I get very stressed when I have very work.
I get very stressed when I have a lot of work.
Use very before an adjective or adverb to say how strong something is: ‘very stressed’, ‘very quickly’. Do not put very directly before a noun to say how much or how many. Use much, many or a lot of: ‘not much free time’, ‘many friends’, ‘a lot of work’.
2
My new car is very faster than my old one.
My new car is much faster than my old one.
My new car is a lot faster than my old one.
Do not use very before a comparative adjective. Use much or a lot to show a big difference: ‘much faster’, ‘a lot faster’.