It's been some times but I swear that it was 250CSC to change a pets name... Did this change recently or am I just remembering wrong?

The price did change, but it dropped. It used to be that you needed an Enchanted Hypnosis Wand, which SubetaLodge says was 1,000 CSC. Since the way you rename pets changed, the price halved. I don't remember it ever being at 250 CSC.

I can't find any info about the pet name change ever costing 250 CSC. The item that used to change a pet's name, the apparently used to cost 1000 CSC (from it's SubetaLodge page). It was changed in 2012 so that the name could be changed directly from the pet's page for 500 CSC, according to this announcement: https://subeta.net/forums.php/read/55228/Pet-Name-Changes

Don't do the same thing I did and buy the: .

It no longer works to change your pet's name. It costs 500CSC to change a name now. The wand used to be 1,000 CSC.

That only happened during Black Friday sales before 2015, and I believe with another surprise sale (which I don't remember when). I don't think it will be offered again in the foreseeable future.