Something like this is probably about the cheapest you can get that will run UE4 good enough to use. It won’t handle larger levels well. With that graphics card you have, your going to need a new pc, not just the CPU as it will probably be a horrible experience if you get it to work. What I’m linking is a a bare-minimum and not something you want for production if your making a commercial game or for school if your doing projects and need it to be very reliable, but should be fine to learn to use the engine with.