What's the 25k+ service Toyota is trying to sell me?

It's not Toyota, it's the dealership, VERY likely likely hardselling.

Mostly you can just stick to the maintenance booklet. The one exception I'd suggest is to get the transaxle fluid changed, say around 15~20K miles, then every 30K thereafter. Service departments try to talk people out of that service, and/or overprice it. It's very straightforward, should not be more than $100. The fluid and washers purchased at parts department are around $40.

 

Follow the books recommendations and skip the dealers con-job.
As suggested, get the CVT fluid changed between 20 and 30K miles.
Don't buy into the dealers hype. It's only to extract money from your wallet
and paying up front just ties you to them for the next service and more hard sell service work.
If you have a service that's needed outside of the Toyota Care freebie, take it to a trusted
indy shop and save money. Dealers overcharge and over sell to make money. They're crooks, IMO.
The freebie Toyota Care is designed to get you use to going to the dealer for everything. Don't fall for it.
Anyone can service the vehicle without causing warranty issue's. Just keep your paperwork

 

Note that while both of the folks who responded are from ca, they are different ca's. It is not clear to me if you are in Canada or California, but you SHOULD have free service at 25,000 in the US.

And as folks are mentioning, follow Toyota's service schedule, not the dealer's. You can add changing the ATF at 30,000 miles and then every 60,000. It may help prevent the Motor/Generators from shorting out and overheating, among other problems

http://lusciousgarage.com/blog/gen_2_prius_2004_2009_transmission_failure_p0aa6_p0a92_p0a7a/

 

Roomate bought some sort of prepaid service agreement when he bought his Gen III. He cancelled it a bit later when he found out it didn't quite cover what they said it did (didn't cover tire rotations), had unnecessary service in it (oil changes every 5k), and was more expensive than the services would be if bought individually ($495 for 10 $50 oil changes, including the two free Toyota Care ones, so actually only 8). He was told quite a different story when he bought it, lesson learned, get paperwork showing what you are purchasing and read it.