If soil test report shows that sand is at a depth not more than 20 feet,you can go for sand piling which is the cheapest option of pile foundation. It is basically excavating the area for foundation and ramming the foundation area with pile filled with sand and 1/4 inch metal up to a depth of 20 feet or where you can find sand.
2.Manual concrete piling
If soil test report shows only mud(clay) and no trace of sand.You might have to do a concrete piling as per suggestions of structural consultant ,this is to bore holes at places in foundation and fill concrete of a richer variety after putting in reinforcement as designed by the structural engineer.
3.Compaction concrete piling
If soil test report shows only mud(clay) and no trace of sand you bore holes to desired depths,fill concrete and then by force ram down reinforcement as per design given to by your structural engineer.