Lap top for 3d modeling with blender and some rendering on budget

with a budget of around £600 / 800$, will a new laptop in this price area be able to run blender tasks such as high poly sculpting, I only render mostly images, so its not a huge issue if it takes a bit of time, my main concern is the ability to be able to sculpt with millions of polys.

If a laptop is able to do this, should i go for a new one, or get somthing more powerfull by buying a refurbished one?

any recomendations or advice is appreciated.

A laptop within an $800 budget won't be very good at anything that requires computing or graphics power. Still, you can look for Intel 12th gen and Ryzen 6000/5000 laptop options in that budget and try finding one that offers a discrete GPU for the best possible performance you can get at that price.
I would say no to the refurb option because the past couple of generations hasn't been too great CPU-wise. But if you can find something with a powerful discrete GPU, it's definitely worth a look.