Both sigma-aldrich and thermoFisher have custom siRNA design. You can design your own or they will design it for you. as for pricing it differs by region and their representative agent which adds service and delivery charges. Merk (Sigma) have a per-designed NEAT1 siRNA (https://www.sigmaaldrich.com/catalog/genes/NEAT1?lang=en®ion=KW) and thermo have more too (https://www.thermofisher.com/order/genome-database/searchResults?searchMode=keyword&productSubTypeSelect=&CID=&ICID=&pearUXVerSuffix=pearUX2&productTypeSelect=sirna&targetTypeSelect=sirna_silencer_select&otherSearch=no&alternateTargetTypeSelect=&alternateProductTypeSelect=&alternateProductSubTypeSelect=&originalCount=&species=Homo+sapiens&otherSpecies=&selectedInputType=&keyword=NEAT1&sequenceInput=&chromosome=-&chromStart=&chromStop=&vcfUpload=&multiChromoSome=&batchText=&batchUpload=&sequenceUpload=&multiSequence=&multiSequenceNames=#filters=primarygenes:^NEAT1$;;).