Costing rhymes with:
defrosting, exhausting, frosting, accosting, adjusting, arresting, assisting, attesting, basting, besting, blacklisting, blasting, boasting, boosting, breasting, broadcasting, bursting, busting, casting, coasting, coexisting, composting, consisting, contesting, contrasting, cresting, defrosting, delisting, digesting, disgusting, divesting, dusting, encrusting, enlisting, entrusting, everlasting, exhausting, existing, fasting, feasting, forecasting, frosting, gusting, harvesting, hasting, hoisting, hosting, ingesting, insisting, interesting, investing, jousting, kersting, kesting, lambasting, lasting, listing, lusting, manifesting, mistrusting, molesting, nesting, osting, ousting, outlasting, pasting, persisting, posting, preexisting, protesting, readjusting, recasting, reinvesting, requesting, resisting, resting, retesting, roasting, rusting, suggesting, tasting, testing, thristing, thrusting, toasting, trusting, twisting, typecasting, uninteresting, vesting, wasting, wresting
Costing sounds like:
cadence, cadences, cadmus, cascading, casting, castings, castonguay, catanese, catatonic, cattanach, cautioning, cautions, ceding, chattanooga, chattanooga's, chattanuga, chatting, cheating, chestang, chetniks, chiding, chitinous, citations, citing, coasting, coating, coatings, codding, coding, coexistence, coexisting, costanza, costanzo, costumes, cotton's, cottons, cuauhtemoc, custodians, customize, customizes, customs, cuteness, cutting, cuttings