You don't need to reinvent your entire wardrobe. That would cost a fortune. Instead, update it. Start by introducing a few up-to-date pieces that reflect your style -- some earrings, a new pair of shoes or a scarf.
Don't be afraid to experiment a little, but take baby steps. If you've been very conservative your whole life, buy one "out there" piece. Shop in places you wouldn't normally go, like an antique clothing store or (if you can afford it) a high-end designer boutique. You might find that you like taking a few risks with your wardrobe.
To save money, try updating what you already have. Do you have an old pair of jeans that's starting to look ratty? Crop or roll them up into Capri pants or shorts. Have a pair of pants that no longer fits? Have them tailored to look like new. Re-invent an old boring dress with a new belt.
Although change is good, it's also important to maintain a core wardrobe composed of a few well-designed and constructed pieces. Keep some classic staples in your closet that you can mix and match to give you more bang for your fashion buck.