It might help to specify your location (at least the country), otherwise the answers will vary greatly solely due to shipping charges.
Do you have a preference for strap type? Dual post, velcro, ratchet?
If you decide to by straps that use L-Brackets, you're probably want to stay away from those with nylon (vs aluminum) L-Brackets.
FWIW: You have posted your question about landboard straps in the Kitesurf equipment section. Not a biggie, but somethng to be aware of in the
future.
ATB,
Sam
"I never had any friends later on like the ones I had when I was 12 - Jesus, does anyone?" - The Body by Stephen King