Anise, fennel (stronger flavour than tarragon), marjoram. thyme, or basil can be subbed for tarragon. Fresh tarragon freezes nicely so the next time you see it fresh in the store, you can buy it and either dry it or freeze it. If you buy a plant, French (the perennial--it goes dormant in the fall and in the house) is better than Russian (an annual). Where I am, the nursery is selling herbs for 60% off. It is a good time of year to buy herb plants at the nursery. Although herb plants like light, heat is not an issue. My rosemary does great at 64-68 degrees F. I mist the herbs daily--that seems to be the key to keeping them alive and producing during the winter months.