IIRC, in New York it’s illegal to absorb sales tax on individual items because by law it’s a consumer tax collected by the business and explicitly not a tax on the business itself, but - and it’s a pretty big exception - anything sold as a bulk good can include the tax in the price. That includes things like liquid fuels, grains or candy by the scoop in the supermarket, loose sand/gravel/salt/whatever for outdoor use, and things like that. It’s been a long while since I had to set up an ecommerce site for New York though.
Who actually pays the tax depends on the Elasticity of the consumer and the business. Who the law says it should be collected from, is really irrelevant.
The law only says by whom and how the tax is collect, it doesn't specify the tax burden, because it can't, that's only observable and happens due to supply and demand.
The guidance published by the state says explicitly that a business collects the tax from the consumer as an agent of the state, and that the taxes collected belong to the state rather than to the business. If it was a tax on the business, then it could be paid later out of the business’s general funds.
Whether you believe the above or not - and I’m not going to discuss that part further, because this is all easy to find online - the fact remains that most sales taxes must be charged separately from the product price at checkout. There are, as I said, exceptions for bulk goods.
