Don't be. Best places on Earth are Furry Conventions. Friendly and easy to relax in
Poco's been saying it right. If the con is within driving distance of your house, then you can easily get away with spending around $100-$200. It all depends on how thrifty you are in the Dealer's Den (the entry fee for a convention is usually around $30-$40, so that's not a big worry), since that's basically where a good portion of your money would go. Heck, if you didn't buy anything in the Den (hard to do, but possible) and the con was close enough, you could go the whole convention for just the price of admission. Don;t exactly recommend that, though, since it feels a bit empty.
When it comes to long-distance cons, it's all but essential to have some mates to go with. Costs go down, there's people to chat with on the way there and back, and a good general sense of companionship. Though it's all definitely something that needs to be worked out a long time in advance, especially when it comes to the hotel. Rooms of the host hotel (and surrounding ones) tend to sell out incredibly fast, so you need to jump on that (and don't forget the convention rate! It cuts the cost of a room each night
way down).
Overall, I agree with the $600 minimum for an out-of-town con, about $250 for an in-town convention (Makir, your situation sounds exactly like me and FC. That's only twenty minutes away from my house, and I went through it using less than $300, and that's only that high because I'm a spend-o-holic in the Dealer's Den
).
Of course, it's all situational, so having a good back-up budget and plan is always advisable.