My cat, Green Eyes, died last November, after a long bout with a brain tumor/oral cancer. I kept her alive 2 months by syringe feeding her baby food, and water, and waking up all the time to put her in the litter box. She finally got down to 2-3 pounds after being 12 pounds. She went blind/deaf in the last month, and couldn’t walk. I finally put her down after agonizing/ and crying every night while I fed her. I didn’t want to “kill” her. I kept trying to get my nerve up to call the vet. I even wished she would just go peacefully in her sleep. I never had to put an animal down before, and I even had a mental breakdown over it. She was my best cat. She was 15 and a half. I cut a lot of fur off her and put it in a Ziploc bag. I even kept her teeth from a previous dental surgery. I paid $75 for the euthanasia, and $25 for a communal ash burial. I don’t think I could go through that mess again, and I have 2 other cats. 
Inividual cremation, ashes returned. I store the ashes in a container that has some meaning for me. For instance, my 2nd cat’s ashes reside in a silk covered Japanese tea tin that was given to me as a ‘thank you’ for taking his cat for 2 weeks while he went home to Japan.
My last deceased pet was a fish so…nothing special really, scooped out of the tank and sent to the landfill.
I let the vet dispose of the body. Nerdy as it is, my view of dead bodies comes from TNG Klingons: The body is an empty shell; it’s occupant has gone. Dispose of it efficiently.
My family has always home buried pets. So my cats have gone in the back yard, two so far, and on small dog.
At-home burial. But my folks live in the country, so it was pretty easy.
(Cats)
Always cremation, loose cremains buried in yard.
Interesting. Despite the fact that the deaths were expected due to age/ilness, I was so emotional-numb-stupefied that I can’t remember what it cost. I just handed over my credit hard in a daze. The vet could have paid her kid’s entire college tuition with the charge and I probably would have just nooded, “Yes, that’s fine.”
I learned at an early age (farm kid) that the physical body is just a shell - so all animals I’ve owned/fostered/cared for that die in my care get the basic “group cremation” or whatever the chespest vet option is.
By now I’ve seen the passing of so many animals - and lived in so many different places - the remains would have long become meaningless and far attenuated both physically and mentally from my current place in life. I have no particular attachment to physical remains of dead family members.
We have the ashes of from our beloved Oops, the sweetest tabby that ever lived. I still think a big part of me died the day I put her down after 20 wonderful years. I’m choked up now, and it’s been six years. Whenever I set up my glass beadmaking setup again, I will put some of her ashes into a special lampworked bead to keep near my heart. God, I loved that little girl.
Jake was euthanized at home - vet made a house call, since the poor old fellow was so terrified of his visits to the doggie doctor. Mom and the doctor and I sat on the floor, crying while the shots took effect. Mom and I then drove out to the family farm and buried him next to Sara the Dalmation and Luke the Peke/Lab (?!) and Baggy the iguana and D.C. (Damn Cat.) Jake has a marker that reads “Jake 1993-2009 Damned Good Dog.”
My rats get mass-buried about every three months (we do necropsies on all deceased breeding stock, then they go in the freezer until it’s time to dig a hole) - it’s not that I don’t love the little buggers, but as a rat breeder, I lose probably 2-3 a month so it stings less and keeping memorial keepsakes would get ridiculous very quickly.
My dogs and cats have each been cremated, and I have received the ashes back, as well as my first bunny. The ashes are individually sealed, and the containers are stored in a very nice little wooden box. When I’m cremated, I’ve asked that the ashes of my pets be mingled with mine before we get planted in the roots of a new sapling.
When my heart dog died, I took a pinch of his ashes and sealed them in a prayer box necklace (http://www.prayerboxes.net/) and I keep it with me. There’s no religious reason, I just miss him.
Group cremation through the vet’s office. We figured she would be a dust collector and we wanted to remember her but still be able to let her go. It was easiest and least expensive. Well, or we could have buried her under a tree in our yard. Don’t think that would have been liked by the city though. 