I am looking to have my Grand Aire 2.5 ton split system heat pump replaced in my home. It has developed a Freon leak and is an older system, almost 14 years old. I reached out to a local reputable company and was quoted $12,500 to replace my system with a same spec system made by Rheem. When I look this model up online, it prices for under $3000.00. Is the price for the system and installation they are quoting me within reason?
Pricing is off-topic, so I'll ignore the actual numbers and just say that it varies a lot by region, by work involved (a straight replacement is very different from also adding electronic air filter, fancy thermostat, fixing up bad ductwork, etc.). Always get at least 3 estimates for nominally the same job (might be different brand system but same size, same add-ons, etc.) because pricing varies. A lot.
But I strongly suggest you consider a heat pump rather than just a replacement air conditioner. There isn't that much more in a heat pump than in a regular air conditioner - essentially it adds the ability to reverse the flow of heat. That can save you a lot on heating, even if you don't need to replace your furnace right now.
Also look at efficiency. In the US that is generally listed as SEER, with the higher the number the better. Then you calculate (based on cooling degree days and the size of your house, etc.) how much you are paying to run your A/C (and possibly heating as well) and how much it will be with different efficiency systems. A few hundred $ a year over the course of 10 years becomes a few thousand $.