Literally thousands, but you must remember that some DIY conservatories may not have the same specifications as a company who only supplies and fits. Remember you get what you pay for. Our advice is if possible purchase the highest specification you can afford, as this will service you well.
You can purchase many types of DIY conservatories from under a thousand pounds to as much as you wish, dependent on size and specification. But remember this will not include the base or base materials and this should be added in when budgeting for your conservatory.