regarding Amsoil Signature Series 0W-20

Looks like there's just more detergents in the oil that makes it super expensive. Probably not worth it. As in the least expensive full synthetic motor oil is going to be almost no different than the most expensive full synthetic.

As for buying quarts versus a gallon the latter is cheaper than the former...

Lastly, it says you need 4.4 quarts but it's very difficult to drain all the oil out of a PrIus. I usually start with 3.5 quarts and then run the engine and then check the dip stick. More often than not, that's in the middle of the range between high and low on the dip stick.

I only fill to top of the range on the dipstick if the owner of the car doesn't check their oil level or bring the vehicle to me consistently.

 

Since both bottles are the same oil, get the one that cost the least.
Do not over fill! Follow what Toyota says. They know their engine best.

 

Depends on your OCI and oil burning rate. I used redline and oci was 14,000 mi with the help of black stone oil lab’s guidance. Had about 40% left of the 5th quart bottle after drain and fill. In between the first initial fill and 14,000 miles driven, the last 40% of the quart was used to keep a consistent top off. Had it been 5,000 mi OCI, the last 40% would have been unused and no top off needed. When using top quality oil, you can go longer than most oil, but get an oil analysis just to be safe. I ran redline for 100,000 mi at least, then the prices were jacked up so now I’m on the purple studf

 

You could buy 2 large ones. Then you'll have some to replace the oil that gets burned.
Then you'll only need to purchase 1 the next oil change.

 

Oil lasts a LOONNGGGG time. Keep the cap on and you'll be fine.
It will EASILY last a year....

 

Amsoil and Ravenol are PAO oil that are more stable than typical HC synthetic or group III Castrol, Total, or Shell. You can do 1 year/10k miles interval without problem with PAO oil. I clasifiy 3 grades of base oil that I may use:
1. Group III or HC synthetic. Castrol, Valvoline, Mannol, Eurolube
2. GTL (gas to oil) from Shell Ultra or Penzoil Platinum Ultra
3. PAO group IV or group V Alkylated Napthalene or Ester oil.
For instance, Castrol or Liquimolly 0W-20 have several choices and the price also difference. The one with Longlife 508/509 is much more expensive than the one with API SP (Asia and America cars).
However, the other factor is the additives package and manufacturers have standardized test. For instance, API SP has 3 more test than API SN and Dexos Gen 3 is even has higher treshold to pass. You can see it in the main additives producer website. Relative Performance Tools

Lubrizol is the one that supply additives and the inventor of ZDDP antiwear.

If I were you @kamrul, I will stick with cheapest API SP I can find and do 5000 miles or 8000 Km interval. It will keep your car better and prevent the nutorious oil consumption later.
For instance, Mannol 7722 508/509, It is HC synthetic but cost €68 shipped to home for 10L. But the API SP 0W-20 Mannol is much cheaper, only €40 for 10L. You see the difference is large. I had tried both of them and they are good.