Maintenance Suggestions, Please @152k miles

Hello friends,
I got my 2012 Prius 3 used, at 100k, in early 2018 (5 years ago). It drives really well, but I've noticed the mpg going significantly down in the past year. I do the regular oil changes myself with high-quality synthetic oil (Castrol Edge 0W-20) and a high-quality oil filter for synthetic oil, and I change the cabin filter and air filter annually. Feeling rather smug that I am doing the required maintenance (duh) I realized last week (I know, please do have a belly laugh) that it also needs the spark plugs changed sometimes! (OMG!)

I called the dealer. They suggested this:

Change 4 spark plugs $299
Change Engine coolant $234 (it was a little low when I checked a few weeks ago, so I bought some pink stuff that the auto parts store said matched my car and topped it up)
Inverter Coolant Drain and Refill $167
Transmission Service $130
Front Brakes $425
Rear Brakes $395 (the Les Schwab tire shop told me about a year ago that brakes would "probably need changing on the next tire change")
Total for all this from the Toyota Dealership is $1650

I know I've had my head in the sand and feel rather stupid about that, but the $1650 sticker price is a real shock for my limited budget. Do you recommend that I do all these things? Since I bought the car at 100k, I don't know when things have been done before. I think the brakes are original (and I'm at 152k). Certainly the spark plugs have not been changed on my watch, so in 52k miles.

So, ahead of time, thank you for your kind assistance. Also - can I go to a local repair shop that has very high ratings for servicing Toyotas instead of going to the dealership? It sounds like the local shop may be cheaper and I'll call them about it tomorrow - or do you suggest I only service the car at the dealership?

Thanks so much!

 

Super helpful, thanks!

 

I'd love that Tesla solution! If I could afford it! Thanks!

 

Thank you, everyone, this has been very helpful. I found a local well-rated shop that will do the whole gig for $425 less than the dealer and is 30 minutes from home, not an hour like the dealer. That's a 25% savings, and they seem very fair and took time to answer my questions on the phone today. I feel pretty "accomplished" as a 65-year-old girl-mechanic changing my own oil and filters each time, but I throw in the towel on learning more and just not wanting to screw it up! Thanks again!