US Dollars? A laptop to run the entire game, meaning all EP/SPs and a solid dose of store content and CC, would tend to start at around $900 and go up from there. We can cut corners, look for sales, etc. and bring things down a bit, but in the under $500 range we would be talking about a class of machine that might be able to run the base game and maybe one or two of the earliest EPs on low to maybe medium graphics settings but even then it would be expected to struggle. Pets and Seasons practically demand a dedicated graphics card of sufficient strength and then a cooling system strong enough to be effective, IP and ITF would be just behind those two, and such features drive the price up considerably over a typical laptop meant for web browsing and light office/school types of tasks.
Desktops run cheaper than laptops generally, with the understanding that you would need a monitor. Would that be a viable way to proceed? Even then we would be hovering around the $700s for a machine that can handle the entire game again subject to sales and cutting corners here and there.