Here's my tip: don't assume that ticket resellers at 3rd party hotels are offering the best deal. The fact is that park tickets (for Disney World or Universal) are rarely sold at a discount on their own. You can sometimes find good package deals though, where a reseller will offer something else that you might want (food vouchers, entrance to another attraction, etc.), and the total price might represent a savings to you...but only if you value everything that's in the package.