The cheapest way to sit in the 100 level is to choose a seat behind the basket or in the corner of the arena. While these seats may not be your first choice, they accommodate a wider range of budgets and there are some pretty good seats if you know where to look.
First, sections 101 and 121 should be avoided almost entirely. These sections are directly behind the basket which makes it difficult to see what's going on at the near hoop and especially on the other end. The only redeeming quality of these sections is that the first row (row D) is just above the tunnels where the players enter the court.
With the exception of the Loge boxes, the best seats in this seating zone are located at the front of sections 106, 116, 126 and 136. The first six or seven rows in these sections have a great angle towards the court and are located just a few steps from the hardwood. We typically don't recommend corner seating in low rows for NBA games, but these seats are an exception.
If the pricetag on the previously recommended seats is too great, aim instead for rows 20-30 of sections 104, 118, 124 and 138. While the view from these seats is slightly bothered by the basket, it's not as bad as is in 101 and 121. Instead, you'll have a decent angle towards and court and you'll be near the tunnel that leads to the concourse and all of its amenities (restrooms and concessions).
Finally, fans will find the aforementioned loge boxes in sections 104, 118, 124 and 138. These 12 boxes feature just 40 seats in total, making them one of the toughest tickets in the arena. Each box features a table and a drink rail and comes with premium amenities like in-seat wait service, personal television monitors and complimentary food and beverage.