Why can't I find any specific fare information for Arriva buses?

Because they don't post it on the web

I'm interested in the 500, 510 and Greenline 724 buses, but there's
absolutely no information anywhere on the net about these fares.

Timetables available, but no fares

Does anybody know the fares for Romford to Harlow on the 500, Harlow
to Stansted on the 510, and Heathrow to Harlow on the 724?

You'll have to phone them on their loverly premium rate number for
Customer Queries

0870 608 7261 for the 724 or email

08701 20 10 88 for the other services

The only fare info on the Arriva Website is at

http://www.arriva.co.uk/REAL/web/Arr...256b0a00571af0

For Harlow it gives details of the season/day tickets below - If there
are 2 of you the Explorer ticket works out at £3.50 each return (or
£1.75 single each way) and covers an enormous area - it's valid on the
724 as well, and almost all operators in Herts accept it.

HARLOW

Harlow Zone - Allows unlimited travel within the Harlow Zone.
Boundaries are as follows: Fifth Avenue, Harlow Mill, Old Harlow -
Sheering Road, Churchgate Street - Slugs Hook, Potter Street - London
Road, Parsloe Road - Sumners Farm, Water Lane - Bradley Road Brookside
and Roydon Road - Speedway.

Adult
Day £2.50
Weekly £8.40
Monthly £33
Child/Concession
Day £1.30
Weekly £4.20
Monthly £16.70

All Zones - freedom of the Arriva the Shires & Essex services in
Bucks, Beds and Herts (not Green Line services to/from London from
Luton and Hemel Hempstead).

Adult
Day £7 (Explorer) or £6.50 (Arriva Go Anywhere)
Weekly £19
Monthly £52.50
Child/Concession
Day £3.50 (Explorer)
Weekly £10.50
Monthly £31.80