What is the difference between 东西 and 用品?
用品 is used for articles that can be used, articles for use (Definitions is 2 dictionaries: 应用的物品 / 供使用的物品).

Some examples:


办公用品: Office supplies, office goods
日用品: articles for daily use
常用品: everyday implement; object of everyday use
床上用品: bedclothes; bedding
体育用品: sporting goods
教学用品: educational supplies, study material


东西 is just a thing.

You should contrast 用品 with 产品.
产品 is something that is produced/manufactured, hence a product (Definitions in 2 dictionaries: 生产出来的物品 / 劳动所创造的物质资料，包括生产资料和消费资料). The last dictionary says it's also used for consumer goods.

So for 用品 the emphasis is more on the usage, and for 产品 it is more on the production.