Why does it say the inventory is not available?

Steam only shares an inventory that is set to Public. The owner can change it under Steam - Edit Profile - Privacy Settings - Inventory. It can also mean the account holds no Rust skins.

How are the skins priced?

At the same canonical price the whole wiki uses: Steam's lowest sell order for the skin, or the highest buy order when nothing is listed. Skins with no Steam market listing show as unpriced and count as $0.

How fresh is the data?

A fresh read from Steam is kept for 24 hours; the Reload link forces a new read. Prices are always today's.

Is the Rust inventory value accurate?

It is what the inventory is worth on the Steam Community Market right now, which is what almost everyone means by inventory value. What you would actually receive in a sale is lower: Steam takes roughly a 15% fee on every market sale, and thinly traded skins can take a long time to sell at the listed price.

Do I need to log in or send a trade offer?

No. Everything is read from public Steam data, so there is no login, no API key and no trade URL - which is also why you can check anyone's inventory, not just your own. It is free with no cap.

Can I see what an inventory looked like before?

Yes. Every day an inventory is checked, a snapshot of its items and that day's prices is saved; pick a date on the result page to view it. The value chart also has longer ranges and a custom date range.

Can I use this from code?

Yes - the rust.wiki API exposes the same lookup at /api/v1/inventory/{steamid} with an API key.

Rust 库存价值计算器

粘贴 Steam 个人资料链接、自定义 URL 名称或 SteamID64，即可按本百科其他部分使用的同一套 Steam 实时价格，为该账号的 Rust 皮肤估值。库存必须在 Steam 上设为公开。免费，无需登录，无需交易报价。

指南： Steam 交易限制：为什么无法交易以及如何查询

已查询的库存

58,640

已查询的总价值

$18,870,038.39

最有价值的 Rust 库存

第 119 页，共 2932 页

#	玩家	物品	价值
2361	FREEKIT.	719	$1,607.69
2362	♡ OhMyJaz ♡	524	$1,607.58
2363	Snarfimus	499	$1,607.25
2364	Woobie	539	$1,607.03
2365	HazZard	167	$1,606.93
2366	TRADE BOT #15	601	$1,606.46
2367	melvin	730	$1,605.92
2368	Roberto Vannacci	556	$1,605.81
2369	Scam Likely	371	$1,604.56
2370	×͜×⁧⁧ Bruxo✞	382	$1,604.51
2371	Lemon Stealing Whore	461	$1,603.76
2372	John Wilkes Booth	365	$1,603.52
2373	Lil Yoda	307	$1,603.04
2374	WERD †	429	$1,602.61
2375	KEVIN	174	$1,602.57
2376	sylar	121	$1,601.82
2377	golden lion	411	$1,601.39
2378	JOOOD	934	$1,601.28
2379	MooMooEntrails	562	$1,600.62
2380	Prince ツ	881	$1,600.58