You can buy it at the Goldenrod Department Store
TM25 Is Thunder.
TM25 is Thunder
Thunder
You get TM25 Thunder in the Power Plant in Pokemon Blue.
you can find it in lilycove department store as tm25
There is no best Pokemon on Pokemon HeartGold.
there is no Pokemon Mansion in Heartgold.
Icirrus city pokemart - cost 70000
They are not in Pokemon HeartGold
If you mistaken as Thunderbolt. It is TM25. You can get it at the Game Corner in Kanto for 10,000 coins or in Cerulean Cave. Thundershock isn't a TM in the SoulSilver or HeartGold.
where is the pokemon transfer lab in heartgold
No, but you can trade Pokemon only in HeartGold to Black