New strings, complete including bass strings average around $3000.00, it doesn’t matter about the size of the piano, string prices are about the same. Bass strings always or almost always have to be duplicated from the old strings. Be careful with universal bass strings, they are mostly made for a quick fix. Re-using old strings doesn’t work. Bass Strings alone can be upwards of 1000.00 *** German Ties*** If a piano has factory German ties ( ndividual knots on the steel strings) you can expect to pay an additional 1500 to the above 3000 number.