Keys in Gourmet Ranch will unlock any crops, animals or seasonal items you wish to grow.
For example here is two rows of the 2011 Halloween Ingredients. If you notice, the first set of items needing to be unlocked take two keys each. The next item should be 3 keys each and so on.
You get TWO keys every time you go up a level. As you can see at my next level, just two keys. Doesn't matter how high you go that is all you will get on every single level.
You can also find keys thru fishing.
As a low level, keys will come fast and furious to you. Its best to not be in a hurry to spend them all right away. The reason for this is two fold. First, as you get higher in levels, the more experience you need, therefore the more time between when you receive keys.
The second is that regular ingredients go on sale once a month or so. This is thru something called the SLOT MACHINE. If you see this down by your neighbor bar, its a good week! There is usually a timer of about 3-4 days.
It will save you up to 50% , so instead of spending 36 keys to unlock a single column, it might only cost you 17 keys. Given that to unlock every single regular in Gourmet Ranch it is a few thousand keys, you really, really want to be frugal about where and when you spend them.
A quick tip on using the slot machine. You are NOT stuck with the first column you are given. If you want a second spin, buy the first item in the column you were offered. So if you are offered a column in vegetables and the first ingredient to unlock is cabbage, unlock it and ONLY it. You will then get another spin on the slot machine for a different column. You only get the discount ONCE each time it pops up. So if it pops up 12 times in a year. Then you can get the discount 12 times. One for each time it appears.
Keys can also be used to unlock avatars though I personally would NOT suggest that. However if you have been playing awhile or you want a more custom ranch it is certainly a way you can add that personal flair.
Be mindful keys might be plentiful as you get started but once you get into those higher levels, It takes longer and longer to accumulate them without using real money. And while you can use GR cash to purchase them, I would also be hesitant as it can get very expensive, really quickly.
Individual keys are priced at 5 GR cash each. Yikes that is pricey, considering on average you only get about 10 GR cash per quest. Which by the way is better spent elsewhere. Like on an expansion or a speedy stove.