|Kayak's "Explore" Tool lets you find vacation ideas based on airfare cost!|
I'll sometimes use this online tool as a starting point for ideas, and then input my exact dates to find airfare and hotel prices. (Even if airfare is reasonable, lodging prices can still break the budget!) One great cost-saving alternative for lodging is Airbnb. Here's a referral link for $25 off your first trip!
Hope this tool can help you with travel destination ideas and save you some money along the way!