Paulie: this is not how you compare prices, the reason that some person on Ebay can sell you some processor for a low price can have numerous causes, one that he overordered for a cancelled production and likes to see some return on his lost money (semiconductors can never be given back), another that he found some reels in a container in the alley and took them home.
Does that mean he can sell you 1 million of those processors if you wanted to go full production: NO.
Does that mean that this is the real cost of that processor: NO.
Does that mean ST sells them for that price: NO.
Give you an example, if you ask nicely I can sent you 10pcs of a STM8S208K8 for the shipping costs of the envelope, does that mean those processors cost 0,00 so are free? NO.
So to compare fairly you should talk to the manufacturer or use the quotes from the same source. Now lets take for instance Farnell that always has too high prices but that is because they give you a service namely you don't have to buy 1 million processors if you only want a few, they have large warehouses where they keep your stuff dry, a lot of personell that will get your stuff and sent it for the next day courier delivery, while on the other hand you had to wait for your container to arrive from China by boat in 2 months time
. Anyway that costs a lot extra so those prices are ofcourse much higher than if you ordered directly with the manufacturer BUT you can at least have a fair comparison if the source is equal.
Take your STM8S003F3P6 and look at Farnell: they cost € 0,365 ex VAT per 1000 pieces and €0,351 per 8000 pieces.
Then look at the STM32F030 and they cost € 0,412 ex VAT per 1000 pieces.
So the cortex M0 costs 13% more than the STM8 (1000 pieces) BUT the Cortex M0 has double flash, quadruple RAM and four times more speed AND it is 32 bits.
STM8S0 STM32F0
Program Memory Size: 8 KB 16 KB
RAM Memory Size: 1 KB 4 KB
CPU Speed: 16 MHz 48 MHz
No. of I/O's: 16 15
I can not disclose or at liberty to disclose the prices what these devices cost if you buy them in large quantities but as I stated in the other topic, the CortexM0 is going to win on price and the reasons are the smaller nm production process (more dies per waver) and also important there are going to be a lot of competitors that are offering the Cortex M0.