@booklover240 I found several models that are affordable and would run TS3 on high settings, and likely TS4 as well, although you'll want a second opinion on that from the TS4 experts.
A couple of notes: First, 8 GB RAM is enough to run either game comfortably, but it would be better to have 16 GB for the sake of future-proofing. All of these models have room to upgrade to 26 or 32 GB later, if you want. Second, TS3 in particular loads everything much faster when installed on a solid-state drive (SSD). (It doesn't make a different for TS4.) You can certainly play off an HDD, but it's going to take longer to load the game itself, your saves, CAS, and travel destinations.
Also, none of these models come with monitors. It's a good idea to pick one out in person, so you can see what it looks like—after all, you'll spend a lot of time staring at it.
This one ($700) has a strong processor and an Nvidia 1050 ti, which should be able to handle both games. The disadvantages of this model are its 8 GB RAM and its small (SSD); you'd need to install both games and keep your user game folders on the larger, and slower, HDD.
https://www.newegg.com/Product/Product.aspx?Item=N82E16883230370
This one ($820) has a weaker, but still strong-enough, processor, and an Nvidia 1050 ti. It has the advantage of a 500 GB SSD, which could hold both games, as well as 16 GB RAM.
https://www.newegg.com/Product/Product.aspx?Item=N82E16883289009
This one ($880) has a processor comparable to the first computer listed, plus it has a better graphics card (Nvidia 1060 6 GB). Its small SSD (240GB) might be enough to fit TS3 and your game folder, although you'd have to be careful to move any saves you're not using to the much larger HDD.
https://www.newegg.com/Product/Product.aspx?Item=N82E16883230367
Finally, I poked around CyberpowerPC's website a bit, and it looks like I could pick out a custom model with an Nvidia 1060 6 GB, a 500 GB SSD and secondary HDD, and various other details for about $1000. (I was hoping to catch the free upgrade to 16 GB RAM, but it looks like that deal ran out at midnight.) If you'd like to go custom, which would mean getting higher quality parts, let me know, and we can talk about what features you'd like to have.