The title says it all. I'm trying to figure out what items I can get for a Shadowrun 4e campagin on roll20
The highest availability available for unlimited purchase during character creation is 12. The "Restricted Gear" 5-pt quality (from Runner's Companion) allows the purchase of any single item up to 20 availability, and may only be taken 3 times.
While this is expressly contrary to the RAW, all GMs I have seen run Shadowrun, myself included, have allowed characters to combine multiple purchases of the quality in order to purchase a single item, rather than just a number of more common items.
Restricted Gear (Original version)
Cost: 5 BP
The character knows just the right person to get ahold of that one elusive piece of restricted gear or miltech weaponry she really needed. Every time the character takes this quality at character creation (max 3 times), she may exceptionally buy a piece of gear with an Availability of up to 20. The character may also save the quality to buy one such item during play.
Restricted Gear (Houserule version) Cost: 5 BP The character knows just the right person to get ahold of that one elusive piece of restricted gear or miltech weaponry she really needed. Every time the character takes this quality at character creation (max 3 times), she may exceptionally treat the availability of one item she purchases as 8 less than normal. The character may also save the quality to buy one such item during play.
In the latter case the highest availability rating possible to acquire during character creation is 36. This has very few practical consequences as the only published items I am aware of requiring more than 28 availability are:
The USS Boston Class Nuclear Submarine, costing more money than you will ever have
The Winter Systems Mercury Ship Laser which, at 1,000,000 nuyen, is almost possible with some min-maxing, but not quite (or, at least, I haven't been able to do it yet).
The Saab-Saaker AIM-27 Sparrow Hawk which, at 8,000-11,000 nuyen, is totally possible and equally not worth it.
A rating 6 nanohive, which is cheap
Heavily modified gear using modification rules that add to availability rather than requiring a separate test
In my experience, many characters have no gear higher than 20 availability at the end of character creation and almost all characters have no gear over 28. A great many non-mage characters have one piece of gear over 12 availability, however-- usually whatever general tool is most important to their role in the team.
Finally, no piece of gear purchased at character creation can have a rating higher than 6 or an Availability higher than 12.
Shadowrun 4 20th Anniversary Core Rulebook, p. 86
First off, sorry for being somewhat vague but I only own the Shadowrun rulebooks in my native language, so I cannot quote, cite pages nor do I know the exact names of abilities.
At character creation, gear must not have a higher rating than 6 and must not have an availability greater than 12.
But you may buy an advantage at character creation for 5 character points that allows you to purchase an item with an availability rating of up to 20. It's called Restricted Gear. You can take it up to three times to purchase three different items.