Don't hunt for brands, hunt for hardware...
These are what your laptop must have:
Graphics Card:
Get a NVIDIA Quadro / AMD FirePro card.
Don't get a NVIDIA Geforce / AMD FirePro card (These are mainly for gaming).

Hard Drive:
HDDs are Ok, but SSDs are way better.

Processor:
Get a fast uni-core processor if you just do modelling and assemblies.
Get a slightly-slower multi-core processor if you make renderings and simulations.

RAM:
16 GB is the minimum. The higher the better.

These requirements are usually all found in Dell Workstations. These are some that SolidWorks suggests:
https://www.solidworks.com/partner-product/precision-workstations

The "best and cheapest" are two terms that generally don't go together.

My suggestion is looking for a used Dell Precision M6600 on sites like eBay. The computers are less than $500 and they work with SW perfectly (I'm on one right now).
It's an older computer, but that's the only way you'll realize you "cheapest" goal.

You can get a used M7730 / M7740 laptop which is much newer, but the price goes to about $2,500. When I tested an M7740 we have at work, it was about 10% faster than my M6600. That's not worth buying (to me) yet.

A properly configured M7750 (the newest) will cost about $3,600.

Other manufacturers make similar workstations, I only mention the Dell brand because I am using one, and they sell many of them, so finding a used one is much easier.