A modem is needed for dial-up connection. All the newer computers have internal modems now...not like in the old days when you needed to have one LOL.
I'm on dial-up at the moment because I live way out in the sticks and there is not cable/broadband/dsl available here. I will have to get satellite and it's expensive!!!! Right now I just don't have the money to invest in it. Hopefully soon.
In the meantime, I use Netzero for $9.99 a month, unlimited access. Yes it is slow, yes it sucks, yes I feel like I'm left behind because I can't d/l anything or watch videos etc etc. But, it beats twiddling my thumbs out here in the woods just looking at the birds and listening to the coyotes
If you are using dialup for short term....it's ok. You will get frustrated with it though. That's a given!
Good Luck!