fixed 4x or fixed 6x?

If fixed, 4x. I think 6x is too much for a fixed power.

I have a Swede 6.5mm Mauser with a 2 3/4x Scout scope. I works great out to 300 yds out on the prairie.
I used it a few years ago on an elk hunt in oak brush and couldn't get a decent view through the scope at 80-100+/- yds . I'm sure a 4x would have been fine but a 6x would have been even better.

Regarding sub-$70 scopes:

Every meal an earthworm eats will taste like dirt. Some dirt assuredly tastes better than other, but imagine their contentment if they ever tasted prime rib.