You are 14 years old and awaiting your first memorable experience of high contrast planetary images. I remember when I was that age, I wanted the same thing, but the choice of telescopes then was tiny compared to today.
After 23 years of observing, using and testing many telescope designs, I would offer the following advice, to be always remembered:
The image quality is everything!
Having a wonderful new shiny telescope, with computer controls and all the eyepieces and accessories you could wish for is OK, but, if you don’t have optics of high quality, then everything else becomes meaningless. It does not matter whether a telescope has GOTO facilities or features the latest craze in telescope technology that many people pay good money for. Without high quality optics, your brand new telescope will still disappoint you on the planets. I have had the opportunity to look through some of the cheaper (but still good-looking) telescopes advertised in the American astronomy magazines, and all of them fail to show (what I would describe as) high contrast images.
High performance refractors (APO’s) can deliver some stunning views of the planets, but all of these are outside your budget.
Try logging on to the following website. www.orionoptics.co.uk E-mail them and explain your requirements. Better still, telephone them and ask to speak to Barry Pemberton (phone number on website). Let him know that you are starting out in astronomy, and want a telescope that will provide a positive start to your hobby. So many people are disappointed with their first scope, and many are put off astronomy because of it.
Explain that although you want to look at some deep-sky objects, your primary interest is the planets. They produce several Newtonian reflectors of simple but effective design. You require a minimum of f/6 focal ratio, f/8 would be even better.
Whatever aperture you decide on, insist, ABSOLUTELY INSIST on a minimum of 1/8th wave primary and flat surface accuracy, and make sure the manufacturer delivers a truly flat flat.
This company manufacture a 114mm f/8, a 150mm f/5 and a 150mm f/8 Newtonian on a German equatorial mount, these may be within your budget. They can also supply 1 ¼” Orthoscopic eyepieces (similar to University Optics in the USA) that will outperform all of the cheaper plossls available.
Whatever you decide to do, remember that if you spend most of your money on the optical quality of a telescope, you will never regret it. Spend the bulk of your money on convenience features, and you will join the majority of amateurs who spend many years, forever changing their telescopes in a never-ending quest for the emotional satisfaction that an image from a great set of optics can provide. Start as you mean to go on. Ignore the hype, read the right optics books, try to understand how telescopes really work and what is important about them. Use what you learn when choosing your equipment, you will be better off than the vast majority.