'Very much' and 'a lot' have a similar meaning, but the usage is different. 'A lot' is used more for things you can count (e.g. A lot of people), or to indicate that an action is carried out to a high degree of frequency (e.g. he shouts a lot). 'Very much' is more used to intensify the degree of a single action. So 'thank you a lot' does not sound grammatically correct to me, as it's a single act of thanking, so adding 'a lot' does not work. 'Thank you very much' is perfectly OK as 'very much' is used to indicate that your act of thanking is meant to a high degree. 'Thanks a lot' is also perfectly OK as 'thanks' is now a countable noun, rather than a single action verb. Hope that helps, Tim

very much vs. a lot = In this case you could just interchange the two for each other. Both are acting as 'adverbs' (i think..), so they are just emphasizing the sentence as a whole. There are differences in other contexts, but here they are acting as adverbs. I like you very much I like you a lot I was looking forward to that very much I was looking forward to that a lot Thanks a lot Thank you very much I hope this helps :) If you have any questions, feel free to ask.

my dictionary says: they are the same thing, especially in colloquial language. "much" is mainly used in negative sentences eg. "I DON'T like it very much"