Probably just need to alter your wash technique a bit. I use cheapish products and get good results with a bit of care taken. I use a hose with snow foam from asda £10. a bucket with asdas finest car shampoo £7 and a new micro fibre wash mit £3 every couple of washes with seperate mit for wheels etc. The key is not to drag dirt across the surface of the finish so keep your bucket, mit and water clean. Maintain the finish with a wax. I am using meguires ultimate liquid wax £35. Goes on easy & buffs up lovely. Jobs a carrot. I am a complete amateur just my experience of what works for me after years of practice lol.

Edit : Never use a hand wash car place.. they will destroy your paint due to not having an effing clue