Yes, you are right you can set different different prices through price-list. By default in Odoo prices are shown on the basis customer's price-list for public and portal user as well.
So in order to check price of different different price-list, Odoo provides a feature. Inside a price-list there is a field "Selectable". Which helps to show the list of price-list on website.
On Odoo website it will be look like that,
Ashish Singh(Team Lead)
Webkul Software Private Limited
but what if the customer-portal user should not see the field to select prices. Instead, the portal user should only see prices assigned in the contact price-list field.
Say B2B customers, portal users, have different price lists based on the performance. If they see all selectable prices, then they chose the lowest price all the time.
When I do not allow selectable price list and only leave one selectable price list, this always gets assigned to the portal user. No other price list is used for price calculation. I dont know how to fix this.
"E-commerce" is not a question - I have edited your post and changed the title to a question - please consider using a question in your title next time so readers don't need to open your post to find out what you are asking.