Hi,
Starting at about a year old my DS (now 2.5) enjoyed trains, and I found a used set on craigslist (
www.craigslist.org), a huge bin of track and trains, for much much less than it would have cost to buy it all separately.
Other enduring toys we got around a year of age that we are still using include: wood building blocks, duplo (the toddler version of lego), a children's keyboard (piano, only about $15 at Walmart but real sounding and 20 or 30 keys), toy food and cooking utensils, ride on toys, fridge magnets both letters and characters and animals, a toy barn with plastic animals.
Around one year old a relative bought my DS a little table with buttons to push, pushing the buttons makes sounds or lights up etc, and he was initially wowed and played with it for a few days, but was quickly bored.
Polly