Unless you already have it, I wouldn't buy an r7-240 as a stop-gap as you save up for a better card.
The i3-4130 is definitely the best of those 3 processors, and still allows you to upgrade to an i5 down the road. (Though I would argue that you should be switching sockets by the time you need an upgrade)
My advice: Get the i3 and survive on its integrated GPU until you can afford a good graphics card, like the 750ti/260x/270 and similar cards.
The i3 has Intel HD 4400 integrated, and while it is by no stretch of the imagination good, you'll be able to get a good video card faster if you don't spend money on the r7-240. The integrated Intel will be enough to get by if you drop graphics settings across the board.