Take soft cuttings in the spring, grow these on for later in the summer.
Collect fallen hazel, birch, willow etc branches and plait these together, make into any frame shape you like for plant supports - this works best on wet wood as dry will be too brittle.
Buy one potted perennial, you can usually split this at least twice.
Shop around for plants, the GC's can be pricier than local nurseries.
For summer planting buy plug plants when they're available (and be warned, these go fast!), grow on for the summer.
Bulk buy compost or soil improver if you can, much cheaper. Alternately, make your own compost, and a country drive through horsey areas will almost certainly yield free horse manure (note that free manure must be composted before going near plants).
More when I remember!