Picking up the frugality theme: you can get the best of both worlds by multi- sowing "Autumn " onion varieties such as Hi Keeper in modules, then planting them out as a clump when large enough. Some can be carefully pulled and eaten as "spring onions" and the rest left to grow on, to make a clump of reasonably sized onions for kitchen use much earlier than Spring planted sets will be ready. Those left in the ground will ripoen to be harvested as Autumn planted sets would be
A packet of seed costs far less than a bag or two of sets, juts check you have a variety suitable for Autumn sowing
PS Every year most of the red ones bolt, so I am not going to grow these this coming season