Though it is recommended to have a good configuration to run Unity, lack of good compute should not stop you from making a game. There are many other game engines like game maker that don’t require high end configuration.
Minimum system requirement for Unity 2021
| Operating System | Windows7, Linux or mac |
| GPU | Should support dx10, 2GB atleast |
| RAM | 4 GB |
| Hard disk | 256GB |
You can try running previous version of Unity if you have a much lower configuration. Unity does not state the exact RAM and harddisk requirement. But anything less than the above configuration. You are going to have a hard time making games.
Cost of the above configuration will be around $400-$500.
Recommended configuration
| Operating System | Windows7, Linux or mac |
| GPU | Should support dx10, 4GB DDR5 |
| RAM | 8 GB |
| Hard disk | 256GB SSD |
This configuration is going to cost you a $100 more than the above one, but you will be able to run Unity smoothly with this.