like most projects, you can spend as much or little as you want

OK, lets allow 2 feet of bar top per person minimum. so you need 30 liner feet more would be better. If you plan on having any bar top games or wifi access points add another foot for each space. Don't count the corners twice if it is L or U
shaped.
And last but not least leave room for the staff to get their orders, 4 foot work for me, Also leave room for you to pass through or build in a flop top. I built my bar for 30 people, u shaped and 24 feet per side. used 9 sheets of plywood for the tops, stained, decorated with coins, old baseball cards, poker chips, etc and covered the whole thing in 1/4 inch of liquid resin and let it cure up. Looks sharp and is easy to keep clean.

I'm looking to build one too. I bought really good plans online and they have a bill of materials included with estimated materials cost. My bar won't be as big as yours, but will only be a couple hundred bucks in materials total. The site I went to has some good info on the process.