Been to biarritz twice and have travelled around france for a month surfing. Heading back now in 1st week of October with my other half for a week.
Accomadation can be as cheap as 15 euro a night to a hell of a price. 2 star is cheap and usal clean in France 15 to 25 euro usaly a night.
some places dont allow surfboards if your bringing your own check with the hotel.
Transport is cheap if you fly into biarritz airport only around 3 euro at most on the bus into the centre. Train and bus allow surfboards on board no problem but longboards are a pain to carry on public transport I dont know how many times I hit people when getting my board of and on public transport.
Avoid the Irish bar in biarritz it's crap. The NEWQUAY bar is excellent crack, cant miss it, it's not far from the casino.
Bar prices at the Newquay - Pint 5 euro. Bottle of wine 12 euro
You can surf in front of the casino in biarritiz or head into Anglet 10min walk. Ripcurl surf shop in front of the casino charges 12 euro half day board hire it's owned by a New Zealand dude. you can book your board in advance has some nice Bear longboards for hire.
Try to speak French it makes life allot easier, french people respect you more for it.

Enjoy!!!! : :smiler
www.petithotel-biarritz.com
Freindly staff will help with your ever need. With in reason. Worth paying for but basic.