we often use "yuan jiao fen " in one sentence or " kuai mao(fen can be omit, because all people know mao after kuai, fen after mao)" in one sentence, we do not often use "yuan mao" in one sentence.
70.00元====qi shi yuan(we don't say 00, It can be omit)
3.90元=====san yuan jiu mao(you are right, but we often say "san kuai jiu". all people know the figure after kuai that means mao. kuai=yuan)
1.25元=====yi yuan er mao wu fen (we alway say "yi kuai liangmao wu")
0.20元======liang mao //// can i just say liang (you can say "liang",you are right)
57.00元=====wu shi qi yuan er
10.10元=====yi shi yuan yi mao (shi kuai yi mao)
455.00元=====si bai wushi wu yuan
135.55元======yi bai san shi wu yuan wu mao wu fen ( you had better say “yi bai san shi wu kuai wumao wu or yi bai sanshi wuyuan wujiao wufen”)
269.40元====er bai liu shi jiu yuan si mao (er bai liu shi jiu yuan si jiao or er bai liu shi jiu kuai si)
783.70元====qi bai ba shi san yuan qi mao (qi bai ba shi san yuan qi jiao)
509.50元=====wu bai ling jiu yuan wu mao(wu bai ling jiu yuan wu jiao)
919.27元====jiu bai yi shi jiu yuan er mao qi fen (iu bai yi shi jiu yuan er jiao qi fen)
800.50元======ba bai yuan wu mao