I tend not to buy new stuff in games unless my team seems *really* weak without it. If it's the kind of game where I can go back and buy stuff if I need to, I usually go straight on to the next section and if the enemies aren't too tough, I keep whatever equipment I had. Usually, by time I really am too weak (or just taking too long to kill stuff), I have more than enough cash to splurge on the best everything for everyone. I remember going through Tales of Symphonia for the longest time with the default equipment.

I think if I had to choose, I would still go test the next-area's enemies first. If they can kill me too fast, I would get armour. If I can survive a few hits, I'd get the weapons first. Generally, I guess I would go for weapons first.