The cheapest way to do landscaping is mulched beds with young native plants, installed yourself, at $1 to $3 per square foot in materials. Compare that with $10 or more per square foot for professionally installed plantings. Bulk mulch runs $25 to $45 a cubic yard delivered, far below bagged prices.
Other low-cost moves: grass seed instead of sod (around 10 cents per square foot versus $1 to $2), pea gravel paths instead of pavers, divisions and cuttings from neighbors instead of nursery stock, and free wood chips from local tree services. Natives also need less water and fewer replacements, so they stay cheap after planting.
Cheap goes wrong when it is piecemeal. Decide the full layout first, then build in stages, after testing layouts on a photo of your own yard with OutdoorBrite's plans.