The GM will inform you of the types of legal tender available and acceptable in the various parts of his game world. He will also give you an equivalent purchasing power so you can understand how much the various currencies are really worth.
Purchasing power describes how much goods and services a certain amount of money can buy. For example, one 1990 dollar can buy a loaf of bread; a dime in 1890 might buy the same loaf of bread. Therefore we can say that an 1890-dime has the same purchasing power as a 1990-dollar. Similarly, a silver piece, newdollar, shilling, or compcredit might be compared to something you are familiar with -- say the cost of a meal. If your GM tells you one silver ducat will buy a good meal for one, you can remember that in purchasing power, it equals around 20 US dollars of 1998.
Of course, in different economies, different worlds, and different levels of technological advancement, different things will be valuable. We assume that the thing being used for comparison (in the above example, a good meal for one) is approximately constant. However, other things might be more or less valuable. For example, a pair of shoes might cost more in a medieval society; but then, they are always custom made, and would probably cost a good deal less than a pair of custom made shoes would in the modern world. On the other hand, a steel frying pan, cheap in the modern world due to mass production, would be a moderate-priced item in a medieval society, and a major investment to people living on metal-scarce worlds.
When you start adventuring, you will have a number of possessions built up over the years. Depending on the game background, you may have it all in a sack on your back at all times, or most of it may be home, in your locker, or back on Terra.
Your background, more than anything else, will determine what you can have. Since equipment (apart from the Special Possessions and Wealth abilities and the Poverty weakness) is not balanced by a point system, there is a lot of room for imbalance. You, or another player, could try to abuse the system by claiming to have much useful or powerful merchandise. GMs will therefore keep a sharper eye on you at this stage than usual; you should not argue with him if he declines a piece of booty you wanted. Some GMs will treat the entire equipment list as a "wish list" and roll dice to see if you have each item on the list. (Of course, basic equipment like clothing, ballpoint pens, tinder and flint, wristcomp/holophones, and backpacks probably should not have to be rolled for.)
When a player asks for an extremely unusual item, ask for an explanation for how that item came into the character's possession. Let the quality of the story decide for you, but if the item would ruin some part of the game you have planned, don't be afraid to say no. Also be on the lookout for possessions that can help you come up with plot ideas. For instance, a spaceship makes it possible for adventurers to get hired to do more jobs by more people; a rare device may require supplies that are hard to find or only available on the black market; a magic talisman may influence the course of events around it to some obscure goal that gets its owners into all kinds of trouble. As always, when players' ideas help you get ideas for adventures, don't turn them down!
You should note where your equipment is as you write it down. Your GM may need to know, to determine if you can get to it easily -- or if someone else can.
Most players will resist keeping track of equipment locations to the death. Do not let them get away with it! At the very least make sure they know who has what; and try as hard as you can to make them decide where on their person (or transportation) each item is stored. This will save you a lot of aggravation later, when a character falls into waist-deep water, is hit on the back with a club during battle, or whatever.
You should pay most of your attention to the things you tend to carry around. If your character owns a house in the suburbs, you do not need to even mention the normal things you have there: "toothbrush, pool table with 14 balls and two cues, garden rake, 133 paper plates..." Only unusual possessions need even be mentioned, if you aren't carrying them with you a lot. The rule to follow is this: If you don't write it down, and later on you want to use it, and the GM doesn't agree that you own one, you are out of luck. On the other hand, if you wrote it down and the GM approved it, he probably won't take it away from you. If you want to have a teakettle, coat-hanger, or vacuum-robot, you can probably safely assume the GM will agree these are common enough; however, a pile of coal, a wall-size map of the world, or a nuclear power cell charger may be safer to write down.
The things you carry around will affect on your ability to perform maneuvers. The effects of armor are taken care of elsewhere. (See the Maneuvering in Armor skill.) Clothing, except for bulky, restrictive, or clumsy clothing, is rarely a hampering factor; if it is, the GM will determine the results. All other carried weight must be considered as encumbrance.
Total the weights of the various things you are carrying. Your GM may want to modify the effective weights of certain things due to bulkiness or imbalance. Record this as Carried Weight on your character sheet.
Later, you will calculate your Carrying Capacity and determining whatever penalties you will accrue for your encumbrance. The GM will apply these penalties in full or part, depending on how significant they become in performing various maneuvers.