Player equipment decisions strongly influences the type of game the GM will be running. This is something that should result from discussion between players and GM before the game concept is solidified, not from reflex action to look up the best gear and take that.

One method is to simply advise the players to police themselves and try to be reasonable. This can have very good results. However, although each players choices can end up being reasonable, they can still be out of alignment with each others gear, being too tough or too weak in comparison.

A further issue are strong weapons and armours tending to perpetuate themselves. A powerful weapon easily destroys a foe, the user picks up ammo from enemy and uses that to get more ammo, a 'reap and reload' cycle. While armour repair opportunities have to be given some time, at which time the PC's with overly strong armour will reinforce their lead.

The method used here is to introduce ammo that can only power weaker weapons, and to limit the number of points armour can be returned to with repair. So, instead of the GM chanting 'No!' at the start of the session, players can be left to make reasonable choices. Then, with ammo for stronger weapons being limited, those weapons become an 'ace in the hole' combat choice, instead of 'I use this weapon all the time and it's boring now, but there's nothing better to use'. It’s a similar choice with armour, if they wear it it'll get worn down, the local repair facilities can only repair it back up to a certain number of points (likely well below its maximum). Best to wear a light suit and save the heavy armour for a climactic battle, since the heavy suit will whittle down and become a light suit over time.

Equipment by Party Level: Game World justification
The positive upshot of this limitation is, ironically, availability. Instead of a boom/bust cycle of finding the best in cities then finding nothing in the villages and wastelands (where the action is), a range of equipment can be spread around without it clashing with the scenario. The village might have a trader/operator passing through, they may have something locked in away in an attic for a rainy day. If your really important they may send runners to where equipment is to be found, for the better stuff. But whatever gear that's at the right level of strength for the characters, is quite easy to find. That right level of strength is based on party level.

Party level is the rounded down average of all the PC's levels added together. When your character starts out in the world, it's like he's at the back of a queue. Imagine your character is fifth level and the GM tells you some first level no body just bought the rifle your character wanted.
'Huh? I deserved that rifle more, I'm not shopping here again…though I might hunt down that no body and…'

Basically there are more people in the world who want good gear than just you. Party level gives you some idea of where you are on the ladder. Shop keepers want to sell to people who buy more and might come back to buy latter, lower level characters have less cash and are more likely to end up dead rather than make a latter purchase. Reputation is important too, its dangerous to sell good weapons to people you can't trust (or it's dangerous not to sell to more experienced people who have a large, nasty reputation trailing them). So the shop you go to might even have the powerful gear you want, but it'll probably just stay behind the counter for some other more experienced adventurer who has reserved it.
'There's only so much of the good stuff around, why should I sell to you?'

Using the Tables
Party level is the rounded down average of all the PC's levels added together. Once you've calculated the party level, simply look on the lists below, find the level then look in the columns on the right to find what weapons are available (obviously weapons from lower levels are available too). These tables were made with the idea that this equipment can be easily found, the players just have to ask around (even in villages) and pay the cost and it's theirs. The pay off for having limited gear is simplicity of acquisition, which lets us get back to roleplay and stay away from 'I want this/that' shopping list issues & time wasting.

Methods for Accessing Better Equipment
Naturally, there are ways to access better equipment. Primarily, the GM can judge the current quality of roleplay and based on that, add a bonus of one to three levels to the party level (obviously he can add more if he wants, but this is the scale I use) for the purposes of acquiring equipment. In addition, PC's who pass a streetwise roll (no experience) can access gear one extra level higher. It can be two levels higher if the PC pays one quarter of the items cost before making and passing a street wise roll (no experience). A fail means they don't find it and they loose their 'deposit'.

Note: Equipment availability lists only go up to level nine. After that it's time for the GM to just think big!
Coming Soon: PA and repair by level, giant robots and repair by level.

Salvage rolls above party level 6: Currently spell availability is only listed up to party level 6 (Primarily since spells improve with level, anyway). If a salvage roll indicates a higher level than six, treat it as if it were three levels lower, but in addition to finding a book version of the spell, a talisman of that same spell is also found (with 1D3 charges left).