You can look around without one. Browsing vendors and reading their profiles is open to everyone, no sign-up needed.
You only need a free account for the things that are personal to you: saving your favourite vendors so you can find them again, messaging a vendor through the site, and leaving a review after your wedding.
Creating it takes about a minute. Go to the Sign In or Register page, choose Register, and fill in your details. It costs nothing. Think of the account as the thing that remembers your shortlist and your messages for you.