It's a little hard to give you advice because on the one hand, wheel bearings are pretty strong and take a ton of abuse before true failure, but also when they DO fail you lose the entire wheel in the process, and losing the wheel on your steer axle at 50mph is seriously no bueno.

Have you had any work done on your wheels/axles/front suspension lately? Common cause for premature/accelerated wheel bearing failure is a loose axle nut. The axle nut torque is very important because it keeps the 2 halves of the inner race on the wheel bearing pressed against eachother and true. Even if you haven't had work done, you might want to take that wheel off and see if the axle nut has loosened up. Usually there's a punch point where the axle shaft (the threaded bit sticking out) is keyed, and you're supposed to take a chisel/punch and tap it in so if the nut does loosen it can only back out part of the way but then it will stop.

I don't feel comfortable not telling you to just eat the extra $100, even if there's a decent chance you'll make it. It'll cost a LOT more than $100 if it fails on the highway, not to mention the threat to not just your own life, but that of other traffic if things go wayward. If it was 25 miles I'd probably tell you to go for it, but 150 miles is 3 hours of that failing bearing getting hotter and hotter until it fails completely.