Get free advice
Garden centre staff are very knowledgeable, so pick their brains! Some nurseries offer free planting plans if you send them details of your garden, while others such as Four Seasons Perennials have planting suggestions on their site. If you want to get professional advice but can't afford a designer, many offer a cheaper postal service. As a first port of call try the Society of Garden Designers.

Shop around
Plant prices vary enormously. Out-of-town nurseries are generally much cheaper than those in cities and you can get fantastic bargains at markets, local fetes, jumble sales and car boot sales. If you wait until the end of a plant's flowering season it will be sold off cheaply, an ideal time to buy in bulk. If you live in a rural area look out for plants on sale outside houses. Finally, mail order can often work out cheaper but be aware that some internet suppliers can be pricy.

Divide and multiply
Most perennials can be divided in autumn, instantly doubling your plant stocks. Learning the art of Propagation, ie growing from cuttings or seeds, is an incredibly economical way of planting. Some plants such as verbena (Verbena bonariensis) are useful self-seeders as just one plant will result in several smaller ones popping up around your garden. And if you like a neighbour's plant, ask for a cutting. Most gardeners love to share!

Grow from seed
It sounds obvious but it's very cheap indeed. It's a particularly inexpensive way of cultivating fast-growing annuals which only last a season such as sweet peas, cornflowers or plants from the clarkia or nigella families. Collect your own seeds from seedheads in autumn and you'll have some for next year or swap them at seed-swapping events around the country organised by HDRA: The Organic Organisation.

Buy carefully
Don't be tempted to buy a large perennial. Once a smaller plant is in the ground it will soon catch up. If you're going to splash out, do it on a plant that will be an instant focal point, such as the New Zealand flax (Phormium tenax), or a tree fern (Dicksonia antartica). Look for the AGM (Award of Garden Merit) symbol on the label and buy reliable plants that won't let you down. Avoid impulse-buying which can be expensive, particularly if it doesn't work! And always follow the 'right plant right place' rule, so if a plant thrives in dry shade you can bet it won't do well in your bog garden.

Cheat!
Instead of buying expensive terracotta pots, buy plastic imitation ones and paint them with a mixture of natural yoghurt and water for a weathered effect. No one will ever know they're not the real thing. Save one-litre plastic bottles which are really handy for watering hanging baskets. Cut them in half and they make good cloches for small tender plants. And by simply drilling some small holes in the bottom of old sinks, watering cans, buckets and wooden wine crates gives you instant containers for plants.