Like the others, i'd say invest in a quality light that can do you good seed to harvest. Depending on efficacy, you'd need 110-120watts for photoperiods and maybe 75watts for autoflowers. the better-distributed the light over that area the better. Efficacy of light is cause for the range of watts needed. Higher efficacy generally lasts longer, too / less heat radiated in tent.
if you are looking to overlap a bit and shave some time off between harvests, a 50-75w light will do you well covering a couple square feet or a 1020 tray and go even smaller to cover less area. Depending on efficacy probably want 22-30watts per sq ft on an 18/6 light cycle -- Maybe not for a seedling, but they'll need fairly strong light not too long after if stretching to 2 weeks under this light.. it can be as simple as some 20-30w tube light if just 1 week of time under it. get it nice and close to the plants and they'll get enough for 6-7 days.
work backward from what you want.. get the size you need.