Surreys going rate is £5 per trip - liquid or tab. Although mushies are the same at £5 per (dried) gram (you need at least 2.5g for a mild/strong trip, 5g and off you go!).
Once or twice a year in a group, hire a cottage for a week and drop about 7 tabs to make sure it's a good one!! I find it's best to take it fairly young, the older you get the more scary it seems (to stay in some vague control)