Well if you're looking to play tourneys i'd say look to spend around £500-£600 on a complete set-up including marker, hopper, air, mask, pack, and some playing gear if you're buying second hand. And maybe up to £1000 if your buying all new gear.
Not personally a big fan of ions, though for the money they are good value. For a starter marker i'd recomend E-Blade cockers, PM5's, Angel speeds.
For air i'd suggest any fibre wrap 1.1 4500 bottle with appropriate preset reg.
For Hoppers VL EVO II's are good if you're on a budget.
For masks i'd recomend JT proflex's, just a personal opinion cause i find them uber comfy.
For packs i've heard allot of good things about Nxe and DYE packs. Though if you're on a budget there are cheaper packs that do the same job.
For playing gear, whatever you like and can afford really. And knee and elbow pads come in handy aswell
Though many would probably disagree with me, these are my opinions.
Hope this helps.