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

58,669

已查询的总价值

$18,870,430.67

最有价值的 Rust 库存

第 317 页，共 2934 页

#	玩家	物品	价值
6321	aka employee	191	$656.74
6322	Ozzz.z	357	$656.65
6323	Korpz	173	$656.55
6324	iGoddessi TTV	141	$656.49
6325	Сукин сын	162	$656.45
6326	obama for president	47	$656.38
6327	InkedUp	281	$656.37
6328	DM Bot # 7217	45	$656.32
6329	Snørlax	180	$656.25
6330	ssk	176	$656.20
6331	Beethee	120	$656.13
6332	DOGMA大佬	108	$656.10
6333	Farmer Bob	358	$655.77
6334	~ Ast2R ~	473	$655.74
6335	StormXpress	431	$655.48
6336	Royal Milk	180	$655.46
6337	buff	273	$655.43
6338	Uranium	406	$655.36
6339	szwedziooo	118	$655.36
6340	Large Oil Rig	255	$655.28