You see, there are hundreds of companies dealing with that sector and you should be aware of all possible peculiarities in order to make the right choice and avoid overpaying. I recommend to start from this cool business management software https://protemos.com/features.html and have an idea of the cost. Hope it can help
ProofHub is a powerful business management software that combines all the features you might need to take care of your business. You can streamline your processes, store and share files, share feedback under one roof with ProofHub. Its mobile app can be used by both Android and iOS users on the go.
Working with clients is very important thing because your earnings directly depend on customer satisfaction. So I recommend you to use this online invoicing service see it here which can make your work with clients much easier and profitable. My friend has a business in UK and these guys helped him a lot and not only in invoicing.