Most Dublin buses will take coins as well as pre-paid tickets and rambler tickets. However, the driver may not offer you change if you don't have the exact change. You will be issued with a voucher for the surplus which you can redeem in Dublin Bus's HQ on O'Connell Street.
Ireland, like most European countries, relies heavily upon public transport within its urban areas. There was a time not so long ago when bus and train users were those who couldn't afford their own transport. Now you'll meet a good cross-section of society on public transport - this is as a result of severe congestion in Dublin and increasing priority for buses and new rolling stock for the railways.
Many Irish/Celtic names have been anglised over the years. Drogheda, like Dublin, had a similar Irish name in Droiched-atha meaning the bridge of the ford. It is a lovely town and famous for its magnificient railway viaduct over the river Boyne. It is also the location of the music school run by the excellent Miss Crilly; she has made a significant contribution to culture in the town. The composer Michael Holohan also hails from the town; his influence is such that he was elected a member of the national arts body Aosdána in 1999. Another feature of the town are the remains of the Blessed St. Oliver Plunkett, martyred in England in 1681 for his 'crimes' as a Catholic - his rermains may be seen at St. Peter's church in the centre of the town. Do remember that this is a place of respect, veneration and pilgrimage.
Booterstown Marsh has long been a haven for bird watchers ("twitchers") in the greater Dublin area. Situated beside the sea, the marsh is tidal and attracts a large number of waders. It is a protected area, despite various attempts by the city council to run a road through it.
The recent reconstruction and refurbishment of Booterstown DART station incorporates a fascinating feature. On the western side of the new footbridge connecting the two platforms, Irish Rail included a platform from which to view the marsh. It is covered, but there is no obtrusive glass or metalwork (see picture). Since it is within the station itself, you will need a valid ticket to gain access to it, although you could alight at Booterstown while passing through, and then resume your journey (technically you are not allowed to break your journey, but since you're not actually leaving the station, and since your ticket is valid on any DART train, I have never had a problem). On the seaward side, a similar platform allows very good views over Dublin bay.
Bray, on the southside DART line is Bri [bree] meaning a hill. The most colourful name in the Dublin area is undoubtedly Killiney (also on the DART) being Cill-inghen (formerly Cill-inghen-Leinin) meaning the church [Cill] of the daughters of Leinin!
Irish place names, Bray Head cliff walk - coming
Train, bus and tram in Dublin 5