Many, probably most, RV dealers have a dump station. It sometimes may not be available for public use, but if they're taking in used RVs to sell or otherwise doing repair work they're going to need to dump tanks from time to time The local dealer near me (Pete's RV) offers free dumping. It certainly would not hurt to enquire at one if you need to dump.
Sometimes it's not much more expensive, or even less expensive, to camp and dump than it is to pay a dump fee. This is always true at Vermont state parks if your RV is over 30 feet long; dump fee is $30, and camp sites range from $18 to $22 depending if it's a prime site or not and if you're a resident or not.
If you have a sewer clean-out at your house in a convenient location, you have your own personal dump station.