"carry" is the present tense.
"have carried" is the present perfect (a type of past tense)
Something important to note about the English present tense, I quote Wikipedia:
Use of the present tense does not always imply present time. In
particular, the present tense is often used to refer to future
events... (My train leaves at 3 o'clock this afternoon). This is
particularly the case in condition clauses...
So you are the using present tense correctly in the first sentence. The second sentence uses a past tense which is not right at all, because you're not talking about how much money you had in the past.
Also, we don't use "carry" to refer to how much money we possess. Generally we use "to have".
One final point, "weekend" needs to have an article/adjective/determiner before it. Most commonly you'll use the definite article (the), or the indefinite article (a).
You should say "the weekend". The definite article "the", as opposed to the indefinite article "a", identifies a particular weekend, and this particular weekend means the next one. You can also say "a weekend", which doesn't specify which weekend, it means one weekend in the future you will go to watch a movie.
So a right way to say what you want to say is:
If I have enough money, I will definitely go and watch a movie
on the weekend.
I know all these rules are confusing. Your first sentence in the question is understandable, it just doesn't sound like native speech. So you would be understood, it would just sound a little strange.