OmNomNom!

This is so easy and cost-effective! It makes a trans-fat-free butter blend that can be spread right from the refrigerator, reduces the saturated fats in the stuff, and is WAY cheaper than buying the similar thing. (Salted butter, on sale, can be bought here for $2/lb. The oils are cheaper, depending on what they are. A prefab spread like this costs $3-4 per 8 oz. here.)

This can be scaled to whatever amount you want to make. Before I got smart, I bought a similar blend a bunch of times, and I've dedicated 3 of the containers from this to holding my own version- so I start with a pound of butter. If you want less, feel free to start with less butter, and scale down the oil, too. Also, the amount and kind of oil is very open to variation; I am thinking about including some flax seed oil in my next batch for health reasons (love those omega-3s!).

Anyway, recipe:

Spreadable butter blend

1 pound salted butter (I like salted for toast etc.; unsalted would work)
around 1.5 cups oil: I'm currently using 1 cup canola and 0.5 cup olive oil
(additional salt- I don't add it, but if the salt in the salted butter isn't enough for you, you might want to do so.)

Put the room-temperature butter in a bowl and beat it till smooth. (If you're adding extra salt, do it here.) Slowly add the oil, beating all the while. Continue to beat, occasionally scraping down until it's pretty smooth. It will be runny.

Pour the results into whatever vessels you like, and refrigerate.

This is very spreadable even when cold, and melts almost instantly. It's great for toast. It has good butter flavor, without the artificiality of margarine (which I grew up on), or trans-fats, and you can use whatever oils you like- and feel free to vary the amount of oil! Anything from 1 cup to 2 cups per 1 pound of butter works, but the more oil, the softer the results in general.