As above , you need to specify the system components you already have. Obviously if you have an AMD motherboard, you are going to need an AMD processor. If you haven't picked a motherboard, I would encourage you to go the Intel route for the simple reason, that you have more and better options for the CPU. You may have a slightly better choice of AMD for a basic inexpensive PC (but even that is debatable).
On the Intel side, I would recommend a LGA 1151 motherboard. This gives you the option using both of the newest Intel series of processors.
In the $175 - 250 range, you have the I5-6500 & I5-7500 at around $200. These are quad core processors at 3.2 & 3.4 GHz.
At $235, you have the I5-6600K & I5-7600K. Theses are quad core processors at 3.5 & 3.8 GHz and are over-clockable. If you can afford it this would be my choice. I would skip the I3 processors.
On the AMD side, you have the FX-8350 at $160 and FX-8370 at about $175. I would probably go with the FX-8370 for an extra $15 -20 more.
One more thing to think about choosing a processor. Don't stress out too much on the price tag. All of these processors are within $75 of each other. You will probably be using it for the next 3 - 5 years. When you consider that it really doesn't make that much difference.
I always suggest spending the extra money when buying a monitor. After all, you are going to be staring at it for a long time. But a processor is hidden, and you only notice it when things slow down . I've thought many times that I should have splurged and got the better processor, but then it's too late.