If I choose to suspend my account do I still have to make monthly payments?

We will be using Dreamhost for a Wordpress site and we will only need it for certain times of the year. Maybe a 4 month period. Do we still have to make monthly payments when we suspend the account temporarily?

what’s the best solution for this?

No. But if you cancel your account, or allow it to become suspended, any data under your account will become subject to deletion. I’d strongly recommend that you keep your account active year-round to avoid having to completely rebuild your site every year.