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

58,813

已查询的总价值

$18,889,564.83

最有价值的 Rust 库存

第 1395 页，共 2941 页

#	玩家	物品	价值
27881	Jacobo	20	$47.34
27882	Pointman	29	$47.33
27883	Hundred Acre Wrist	42	$47.33
27884	Maiden	22	$47.32
27885	(HB) Lady Bug	23	$47.31
27886	Micerinos#bestrustserver	61	$47.30
27887	syno	24	$47.30
27888	KebabuValdovas	21	$47.30
27889	Espartaco !	47	$47.29
27890	LaoPao	29	$47.29
27891	koin	22	$47.28
27892	kxr3nn	29	$47.28
27893	DM Bot # 8233	47	$47.27
27894	norecoil.exe	36	$47.27
27895	DM Bot # 8114	45	$47.27
27896	I have diploma in grubbing	25	$47.27
27897	ImMature	35	$47.26
27898	LampieLex	33	$47.26
27899	GALACTIC	64	$47.25
27900	ʕ•ᴥ•ʔ	38	$47.25