CRM users mix levels

CRM users mix levels

Do all agents have to be at the same level within the organisation?,  ie I have some that require mainly sales functions,  so they only need a full crm with products and quote ability,  some that cross over so they need desk and basic crm 
obviously to keep my costs to a minimum this would be ideal to have say a combination of free and professional users (or above)
but I dont know if this is possible or not

Kevin