Short answer — common places and ways to get free delivery for clothes in Singapore:

• ZALORA — free delivery with ZALORA VIP (yearly sub ~S$17.90) gives unlimited free delivery with no minimum; non‑members get free shipping on orders over a minimum (varies / sold-by‑ZALORA items). (ZALORA.sg)
• UNIQLO Singapore — free click & collect (store pickup) and free home delivery on online orders above about S$69 (check site for exact current threshold). (UNIQLO.com)
• Zara Singapore — free in‑store pickup; home or drop‑point delivery is free for orders above S$79 for non‑discounted items (otherwise a delivery fee applies). (Zara.com)
• Marketplaces (Shopee, Lazada) — they frequently issue free‑shipping vouchers or sitewide shipping campaigns and sellers may offer free delivery above their own thresholds; check the app’s voucher/wallet/campaign pages before checkout. (examples of marketplace free‑shipping behaviour are common; check the platform for current vouchers.) (brandradar.org)

Quick tips to get free shipping:

• Combine items to meet the retailer’s free‑shipping threshold.
• Use click & collect / store pickup (often free). (UNIQLO.com)
• Subscribe to retailer membership services (ZALORA VIP, retailer loyalty programs) if you shop there often. (ZALORA.sg)
• Look for first‑order / app‑only promotions and free‑shipping vouchers before checkout on marketplaces. (brandradar.org)

If you want, I can look up a specific brand’s current free‑shipping threshold or check live free‑shipping vouchers on Shopee/Lazada/ZALORA right now.