2k is not a lot of money for a cash-hungry business, but there's no reason you can't get started and then use LOCs to scale one you know what you are doing. Minimum subscriptions you'll need are Keepa, SellerAmp, Sellerboard, and a repricer like BQOOL or Aura. Repricer is possibly optional if you don't mind manually repricing a couple times a day.