For in-store pickup only and with stock varying by ZIP code, PetSmart discounts a selection of Top Fin Essentials Aquarium Starter Kits in various sizes with prices starting at $20, as listed below. That's a savings of up to $100. The sizes: 5-Gallon for $20 ($20 off) 10-Gallon for $32.50 ($33 off) 20-Gallon for $47.50 ($48 off) 29-Gallon for $65 ($65 off) 37-Gallon for $75 ($75 off) 55-Gallon for $100 (pictured, $100 off)