For general boat selection, as others have said, you should be able to find something in the $20-$30K range easily for that size, depending on age and condition. Or less: here's a Catalina 27 for $5000: For Sale: Catalina 27- $5000 - Cruisers & Sailing Forums
Whatever you choose, determine what makes you feel like you're camping out and address that, otherwise your dream will be short-lived.
Some people believe it best to buy an inexpensive boat and then put in the systems *they* want, if you have the time and skills, you end up with a boat that you know intimately, and learn a lot in the process. This is great if your plans call for living at the dock for a couple of years before heading out (maybe while waiting for that big promotion?) Others prefer getting a boat with many/most of the systems already in place - it may be cheaper in the long run, but you miss the knowledge & control gained.
Can you take a liveaboard/learn to sail course? That will give you familiarity with big boats and their systems, and a better sense of what you're getting into.
Cruising will cost as much or as little as you want, depending on how often you stay in marinas vs anchored out; how complex your boat systems are and how much of the maintenance you do yourself; and what shoreside entertainments you enjoy. Here's our budget for two people cruising the ICW from the Chesapeake to Florida on a 33-footer: The "Life Afloat" Archives: Cost of Living ... Afloat
but realize that about $1000 of that is discretionary as ChucklesR pointed out in an earlier thread: if you don't have money for fuel, you sail; if you don't have money for dinners out, you cook aboard; if you don't have money for marinas; you anchor out; and if you don't have money for entertainment, you play cards in the cockpit.