Sell services instead products
I'm a webdesigner freelancer then I sell services instead of products, and each service (a webdesite for example) can have a different price for each case, customer or project. I made a test generating a new estimate to myself and, in "New estimate" screen we have no option to set the price. The same happens with "Items" list, so, I can't set a price individually to the same item, which could be "Webdesign" or "Web development".
In conclusion, I inserted a new item in Zoho Invoice called "Webdesign services" however I can't set a fixed price for that item, because prices aren't the same forever. So, how to proceed in that case? What can I do to handle Zoho Invoice in a way to sell services with a lot of variable prices instead of products which always have a fixed price? Shouldn't we have the possibility to leave price blank on the "Items" list and only set a price when generating an estimate and, after, an invoice?