Simply play 100 ONLINE games as a Human.
Humans start out with $2,500 to spend. Enough for a sniper rifle. Also, don't forget that humans have no essence penalty when using tech.
Some side notes I pulled from Xbox360Achievements.org that are must read, provided by Smokez.
All the achievements will unlock at the end of the match. If you quit early, disconnect, or are booted out of a match, nothing you did during that match will count. If the server (not you) leaves, and you see the "The Server has disconnected" screen, your stats will count, and you will credited with a win regardless of the score. Remember, teamkills will not count in an way towards any achievement. All totals will only count when the match has at least four human (as in non-CPU, not the Shadowrun race) players on each side.
In order to boost:
1) Start up a private party and invite at least 7 other people.
2) Bring the party into a Private Match.
3) Arrange the teams, and make sure all players have marked themselves 'ready'.
Make sure all players know exactly what they need to do, and start the match.