Heed Pitts2112's warning - entry into the world of aerobatics is a one-way ticket to a highly addictive pastime!
Since the demise of the ab initio type trainer and the adoption of the largely universal spamcan specifically designed to avoid anything remotely unstable, opportunities to sample anything much beyond straight and level are few. There was a time when when Tiger Moths and Chipmunks were freely available and spin recovery was part of the PPL syllabus.Things have changed.
I am an old Nepean Bishop pupil and cut my teeth on an inverted system Stampe. But where do you find one of those these days? I moved on to Jungmeister, Arrow Active, S2, Z526 and others but these have gone too. Now, the Victa Air Tourer was a good starter aircraft with a modest negative capability but I suspect they have become pots and pans as well.
Frankly, I think you would be wasting your money buying hours in something like a C150. It will teach you absolutely nothing; certainly not the precision and discipline needed for safe and effective aerobatic flying - and you won't get many Aresti symbols on your sheet either! My advice, supposing the distance from where you are to be acceptable, would be to approach the Tiger Club (no longer at Redhill I understand). Their Macauley Trophy was something I enjoyed immensely and they used to have first class instructional people. However, there was a minimum hours requirement for membership.
Good luck. But be careful you don't start something you can't stop. It's heady stuff!