In that hotel price range, you'll have a wide choice of beach-side hotels.
And the $100/day will easily cover you for the type of eating you describe and your drinks (unless you're a really big drinker).

Your budget is higher than places I have stayed and can recommend from experience - like Legends, Negril Beach Club Condos, and Tree House - which are all close to the nightlife action. But then again, prices I am used to were during low season and discounted from their regular rates by using the various travel web sites - you will be in Negril during high season.

If I had your budget, I know Coco La Palm always gets good reviews and recommendations, and is centrally located on the beach. I see they even have an Early Bird Special going right now for the time you will be there:
http://www.negrilonestop.com/cocolapalm_rates.shtml
It would me my first choice, given you seem like AI is not what you are looking for - you mentioned you hope to walk to many nearby bars/restaurants.

Re traveling solo - this thread was from a traveler who worried she would end up solo for a few days.
Had lots of good advice and reassurance.
http://negril.com/forum/showthread.p...ng-is-a-mess-(